CN114362695B - Information transmission system directly driven by AC small signal - Google Patents

Abstract

The information transmission system directly driven by the AC small signal uses the AC power supply line to provide the AC small signal such as the power frequency signal to drive the oscillator, the amplifier and the mixer; the oscillator is used to generate the output signal containing the change information of the external physical quantity and pass through the first transmitting antenna. Transmit, use the first receiving antenna to receive the signal transmitted by the first transmitting antenna and send it to the amplifier for amplification, use the mixer to receive the signal amplified by the amplifier and mix the frequency to generate a signal that meets the output frequency requirements, and then send it to the second transmitting antenna. After transmitting, the signal transmitted by the second transmitting antenna is finally received by the second receiving antenna and sent to the demodulation network to complete the demodulation of the information. The microwave device in the present invention utilizes the parasitic capacitance and inductance of the transistor below the threshold voltage to form a resonance frequency selection network in series or in parallel to realize parametric amplification, so that the microwave device of the present invention can be driven by AC small signals, and solves the problem that the traditional microwave device needs DC power supply various problems.

Description

Information Transmission System Directly Driven by AC Small Signal

technical field

The invention belongs to the technical field of electronic power, the technical field of sensors and the field of information transmission, and relates to a system for information transmission directly driven by an AC small signal.

Background technique

The world has entered the information age, and information plays an important role in all walks of life. In modern society, there are more and more channels for people to obtain information. In addition to traditional channels such as newspapers, radio, and television, the Internet and mobile phones have increased the number of ways for people to obtain various types of information. In particular, people's awareness of the importance of information is becoming more and more popular. And in-depth, information monopoly is broken, and a lot of information is shared by people. There are also various ways of transmitting information. The main way and means for people to obtain information in the field of nature and production is through sensors. Sensors have already penetrated into a wide range of fields such as industrial production, space development, ocean exploration, environmental protection, resource survey, medical diagnosis, bioengineering, and even cultural relics protection. It is no exaggeration to say that almost every modernization project is inseparable from a variety of sensors.

The information acquired by the sensor can be transmitted by wired or wireless means. Wired transmission includes telephone, fax, telegram, television, etc.; For example, the analog transmission and digital microwave transmission used to transmit video are now used. Digital microwave transmission is to encode and compress the video first, then modulate it through the digital microwave channel, and then transmit it through the antenna. The receiving end is the opposite. The antenna receives the signal, decompresses the microwave, and finally restores the analog video signal. The analog microwave transmission is to directly modulate the video signal on the microwave channel and transmit it through the antenna. The monitoring center receives the microwave signal through the antenna, and then demodulates the original video signal through the microwave receiver. Effective information acquisition and information transmission are of great significance to residents' daily life, enterprise development and even national security.

Traditional microwave devices are based on transistors to achieve amplification, and transistors require DC power for power supply. However, for the existing AC mains with an operating frequency of 50 Hz, in order to obtain the DC power required by electronic equipment, various AC-DC conversions must be performed. , which brings energy conversion loss, and the conversion device also brings cost overhead.

SUMMARY OF THE INVENTION

Based on the shortcomings of large energy waste and high cost overhead caused by microwave devices in traditional information transmission devices requiring DC power supply, the present invention designs an information transmission system based on a microwave device that does not require DC power supply, and uses AC power instead of DC power to directly It can also be driven when the amplitude of the alternating current is as low as 0.1V. Therefore, the transmission system proposed by the present invention has the characteristics of direct alternating current drive, low energy consumption and wide application range.

In the information transmission system proposed by the present invention, the AC driving operation of the microwave device is based on the time-varying driving of the equivalent reactance of the transistor with a small AC signal (such as a power frequency signal) below the threshold voltage of the transistor, and the time-varying driving can To achieve parametric amplification, a single transistor can be used to achieve amplification in half a power frequency cycle, and two transistors can be used to achieve full power frequency cycle amplification.

The present invention adopts a single transistor to realize the technical scheme of the half-cycle power frequency direct drive information transmission system as follows:

An information transmission system directly driven by an AC small signal, including an AC power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network, the The information transmission system works in the half cycle of the AC small signal working cycle, and the frequency of the AC small signal is less than one tenth of the transmission frequency of the first transmitting antenna or the second transmitting antenna; the AC power supply line provides the The AC small signal is used to drive the oscillator, amplifier and mixer; the oscillator is used to generate an output signal containing external physical quantity change information and transmit it through the first transmitting antenna, and the first receiving antenna receives The signal transmitted by the first transmitting antenna is sent to the amplifier for amplification, and the mixer receives the signal amplified by the amplifier and mixes the frequency to generate a signal that meets the output frequency requirements, and is then transmitted by the second transmitter. The antenna transmits, and the second receiving antenna receives the signal transmitted by the second transmitting antenna and sends it to the demodulation network to complete the demodulation of the information;

，

为所述第一反馈网络的初始谐振角频率，设置所述第一输出选频网络的工作频率等于

；所述第一馈电网络包括第一高通支路和第一低通支路，所述第一晶体管的漏极和源极其中一端连接地电平，另一端一方面输出信号连接所述第一反馈网络的输入端和所述第一高通支路的输入端，另一方面连接所述第一低通支路的输出端输出的信号；所述第一反馈网络的输出端输出的信号连接所述晶体管的栅极；所述第一低通支路的输入端连接所述交流小信号；所述第一输出选频网络的输入端连接所述第一高通支路的输出端，其输出端产生所述振荡器的输出信号；令所述第一反馈网络的谐振角频率与外界物理量的变化有关，则所述振荡器的输出信号包含了所述外界物理量的变化信息；The oscillator includes a first transistor, a first inductor, a first feedback network, a first feeding network and a first output frequency selection network, and uses the parasitic capacitance of the first transistor below the threshold voltage to be connected in series or in parallel with the first inductor to form resonance Frequency selection network, set the capacitance value C ₁ of the parasitic capacitance of the first transistor and the inductance value L ₁ of the first inductance to satisfy

,

For the initial resonant angular frequency of the first feedback network, set the operating frequency of the first output frequency selection network equal to

; The first feeding network includes a first high-pass branch and a first low-pass branch, one end of the drain and source of the first transistor is connected to the ground level, and the other end is connected to the first output signal on the one hand. The input end of a feedback network and the input end of the first high-pass branch are connected to the signal output by the output end of the first low-pass branch on the other hand; the signal output by the output end of the first feedback network is connected to the gate of the transistor; the input end of the first low-pass branch is connected to the AC small signal; the input end of the first output frequency selection network is connected to the output end of the first high-pass branch, and its output The output signal of the oscillator is generated by the terminal; if the resonant angular frequency of the first feedback network is related to the change of the external physical quantity, the output signal of the oscillator contains the change information of the external physical quantity;

，设置所述第一输入选频网络和第二输出选频网络的工作频率等于

，

为所述放大器的输入信号角频率；所述第一接收天线接收的信号作为所述放大器的输入信号并连接到所述第一输入选频网络的输入端，所述第一输入选频网络的输出端输出的信号连接第二晶体管的栅极；所述第二馈电网络包括第二高通支路和第二低通支路，第二晶体管的漏极和源极中一端连接地信号，另一端一方面输出信号连接所述第二高通支路的输入端，另一方面连接所述第二低通支路的输出端输出的信号；所述第二低通支路的输入端连接所述交流小信号，所述第二高通支路的输出端连接所述第二输出选频网络的输入端，所述第二输出选频网络的输出端产生所述放大器的输出信号；The amplifier includes a second transistor, a second inductor, a first input frequency selection network, a second feed network and a second output frequency selection network, and is formed by using the parasitic capacitance of the second transistor below the threshold voltage and the second inductor in series or in parallel Resonant frequency selection network, set the capacitance value C ₂ of the parasitic capacitance of the second transistor and the inductance value L ₂ of the second inductance to satisfy

, set the operating frequency of the first input frequency selection network and the second output frequency selection network to be equal to

,

is the angular frequency of the input signal of the amplifier; the signal received by the first receiving antenna is used as the input signal of the amplifier and is connected to the input end of the first input frequency selection network. The signal output from the output terminal is connected to the gate of the second transistor; the second feeding network includes a second high-pass branch and a second low-pass branch, one end of the drain and source of the second transistor is connected to the ground signal, and the other On the one hand, the output signal of one end is connected to the input end of the second high-pass branch, and on the other hand, it is connected to the signal output by the output end of the second low-pass branch; the input end of the second low-pass branch is connected to the AC small signal, the output end of the second high-pass branch is connected to the input end of the second output frequency selection network, and the output end of the second output frequency selection network generates the output signal of the amplifier;

，设置所述第三输出选频网络和第二反馈网络的工作频率等于

，

为所述混频器的本振信号角频率；所述第二输入选频网络的输入端连接所述放大器的输出信号，其输出端输出的信号连接第三晶体管的栅极，设置所述第二输入选频网络的工作频率等于所述放大器输出信号的频率；所述第三馈电网络包括第三高通支路和第三低通支路，所述第三晶体管的漏极和源极其中一端连接地电平，另一端一方面输出信号连接所述第二反馈网络的输入端和所述第三高通支路的输入端，另一方面连接所述第三低通支路的输出端输出的信号；所述第二反馈网络的输出端输出的信号连接所述第三晶体管的栅极；所述第三低通支路的输入端连接所述交流小信号；所述第三输出选频网络的输入端连接所述第三高通支路的输出端，其输出端产生所述混频器的输出信号。The mixer includes a third transistor, a third inductor, a second input frequency selection network, a second feedback network, a third feed network and a third output frequency selection network, and uses the parasitic capacitance of the third transistor below the threshold voltage to be the same as the frequency selection network. The third inductance is connected in series or in parallel to form a resonant frequency selection network, and the capacitance value C3 of the parasitic capacitance of the _third transistor and the inductance value L3 of the _third inductance are set to satisfy

, set the operating frequency of the third output frequency selection network and the second feedback network equal to

,

is the angular frequency of the local oscillator signal of the mixer; the input end of the second input frequency selection network is connected to the output signal of the amplifier, and the signal output by the output end is connected to the gate of the third transistor, and the The operating frequency of the two-input frequency selection network is equal to the frequency of the output signal of the amplifier; the third feeding network includes a third high-pass branch and a third low-pass branch, and the drain and source of the third transistor are in the middle One end is connected to the ground level, and the other end of the output signal is connected to the input end of the second feedback network and the input end of the third high-pass branch on the one hand, and the output end of the third low-pass branch is connected to the output on the other hand. The signal output by the output end of the second feedback network is connected to the gate of the third transistor; the input end of the third low-pass branch is connected to the small AC signal; the third output frequency selects The input end of the network is connected to the output end of the third high-pass branch, and the output end of the network generates the output signal of the mixer.

Specifically, if the sources of the first transistor, the second transistor and the third transistor are connected to the ground signal, the information transmission system works in the positive half cycle of the AC small signal working cycle; When the drains of the transistor and the third transistor are connected to the ground signal, the information transmission system operates in the negative half cycle of the AC small signal working cycle.

Specifically, the first feedback network includes a variable capacitor, a fourth inductor and a fifth inductor, and the fourth inductor and the fifth inductor are connected in series with the variable capacitor in parallel with the input terminal and the output of the first feedback network Between the terminals, the series point of the fourth inductor and the fifth inductor is grounded; the capacitance value of the variable capacitor changes with the change of the external physical quantity;

The second feedback network includes a first capacitor, a ninth inductor and a tenth inductor, and the ninth inductor and the tenth inductor are connected in series with the first capacitor and are connected in parallel between the input end and the output end of the second feedback network , the series point of the ninth inductor and the tenth inductor is grounded; the capacitance value of the first capacitor is a fixed value.

Specifically, the first feedback network includes a variable inductor, a second capacitor and a third capacitor, and the second capacitor and the third capacitor are connected in series with the variable inductor in parallel and connected to the input end of the first feedback network and the output terminal, the series point of the second capacitor and the third capacitor is grounded; the inductance value of the variable inductor changes with the change of the external physical quantity;

The second feedback network includes a sixth inductor, a sixth capacitor and a seventh capacitor, and the sixth capacitor and the seventh capacitor are connected in parallel with the sixth inductor in parallel between the input end and the output end of the second feedback network , the series point of the sixth capacitor and the seventh capacitor is grounded; the inductance value of the sixth inductor is a fixed value.

Specifically, the first low-pass branch, the second low-pass branch and the third low-pass branch have the same structure, the first low-pass branch includes a seventh inductor and a fourth capacitor, and one end of the seventh inductor It is used as the input end of the first low-pass branch and is grounded after passing through the fourth capacitor, and the other end is used as the output end of the first low-pass branch;

The first high-pass branch, the second high-pass branch and the third high-pass branch have the same structure, the first high-pass branch includes an eighth inductance and a fifth capacitor, and one end of the fifth capacitor serves as the first high-pass branch The input end of the circuit, the other end of which serves as the output end of the first high-pass branch and is grounded after passing through the eighth inductor.

The present invention adopts two transistors to realize the technical scheme of full-cycle power frequency direct drive information transmission system as follows:

An information transmission system directly driven by an AC small signal, including an AC power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network, the The information transmission system works in the full cycle of the AC small signal working cycle, and the frequency of the AC small signal is less than one tenth of the transmission frequency of the first transmitting antenna or the second transmitting antenna;

The AC power supply line provides the AC small signal for driving the oscillator, the amplifier and the mixer; the oscillator is used to generate an output signal containing external physical quantity change information and transmit it through the first transmitting antenna , the first receiving antenna receives the signal transmitted by the first transmitting antenna and sends it to the amplifier for amplification, and the mixer receives the signal amplified by the amplifier and mixes the frequency to generate a signal that meets the output frequency requirements. After the signal is transmitted by the second transmitting antenna, the second receiving antenna receives the signal transmitted by the second transmitting antenna and sends it to the demodulation network to complete the demodulation of the information;

The oscillator includes two oscillating units and a first power combiner, and the first power combiner is used to combine the output signals of the two oscillating units into one signal as the output signal of the oscillator;

Each of the oscillating units includes a first transistor, a first inductor, a first feedback network, a first feeding network and a first output frequency selection network, the first feeding network includes a first high-pass branch and a first low-frequency branch The gate of the first transistor is connected to the signal output by the output end of the first feedback network; the input end of the first low-pass branch is connected to the small AC signal; the first output frequency selection network The input end is connected to the output end of the first high-pass branch, and its output end generates the output signal of the oscillating unit;

The first one of the oscillating units works in the positive half cycle of the AC small signal working cycle, wherein the source of the first transistor is connected to the ground signal; on the one hand, the drain of the first transistor outputs a signal connected to the first high-pass branch The input end of the circuit and the input end of the first feedback network, on the other hand, connect the signal output by the output end of the first low-pass branch;

The second oscillating unit works in the negative half cycle of the AC small signal working cycle, wherein the drain of the first transistor is connected to the ground signal; on the one hand, the source of the first transistor outputs a signal connected to the first high-pass branch The input end of the circuit and the input end of the first feedback network, on the other hand, connect the signal output by the output end of the first low-pass branch;

，设置所述第一输出选频网络的工作频率等于

，

为所述第一反馈网络的初始谐振角频率，两个所述振荡单元中所述第一反馈网络的初始谐振角频率相同，令两个所述振荡单元中所述第一反馈网络的谐振角频率都与同一个外界物理量的变化有关，则所述振荡器的输出信号包含了所述外界物理量的变化信息；In each of the oscillation units, the parasitic capacitance of the first transistor below the threshold voltage and the first inductance are connected in series or in parallel to form a resonance frequency selection network, and the capacitance value _C1 of the parasitic capacitance of the first transistor and the inductance value L of the first inductance are set. ₁ Satisfaction

, set the operating frequency of the first output frequency selection network to be equal to

,

is the initial resonant angular frequency of the first feedback network, the initial resonant angular frequency of the first feedback network in the two oscillation units is the same, so that the resonant angle of the first feedback network in the two oscillation units If the frequencies are all related to the change of the same external physical quantity, the output signal of the oscillator contains the change information of the external physical quantity;

The amplifier includes a first power divider, a second power combiner and two amplifying units, and the first power divider is used for dividing the signal received by the first receiving antenna into two signals and then connecting them to two signals respectively. The input end of the amplifying unit, the second power combiner is used to combine the output signals of the two amplifying units into one signal as the output signal of the amplifier;

Each of the amplifying units includes a second transistor, a second inductor, a first input frequency selection network, a second feed network and a second output frequency selection network, and the input terminal of the first input frequency selection network serves as the amplification The input terminal of the unit, the signal output by the output terminal is connected to the gate of the second transistor; the second feeding network includes a second high-pass branch and a second low-pass branch, and the input of the second low-pass branch The output end of the second high-pass branch is connected to the input end of the second output frequency selection network, and the output end of the second output frequency selection network outputs the output signal of the amplifying unit ;

The first amplifying unit works in the positive half cycle of the AC small signal working cycle, wherein the source of the second transistor is connected to the ground signal, and the drain of the second transistor on the one hand outputs the signal connected to the second high-pass branch The input end of the circuit, on the other hand, is connected to the signal output by the output end of the second low-pass branch;

The second amplifying unit works in the negative half cycle of the AC small signal working cycle, wherein the drain of the second transistor is connected to the ground signal, and the source of the second transistor on the one hand outputs the signal connected to the second high-pass branch The input end of the circuit, on the other hand, is connected to the signal output by the output end of the second low-pass branch;

，设置所述第一输入选频网络和第二输出选频网络的工作频率等于

，

为所述第一接收天线接收信号的角频率；In each of the amplifying units, the parasitic capacitance of the second transistor and the second inductance below the threshold voltage are used in series or in parallel to form a resonance frequency selection network, and the capacitance value C2 of the parasitic capacitance of the _second transistor and the inductance value L of the second inductance are set. ₂ Satisfaction

, set the operating frequency of the first input frequency selection network and the second output frequency selection network to be equal to

,

is the angular frequency of the signal received by the first receiving antenna;

The mixer includes a second input frequency selection network, a second power divider, a third power combiner and two mixing units, and the input end of the second input frequency selection network is connected to the output signal of the amplifier, The output end is connected to the input end of the second power divider, and the operating frequency of the second input frequency selection network is set equal to the frequency of the output signal of the amplifier; the second power divider is used to divide the second power divider. The signal output by the input frequency selection network is divided into two signals and then connected to the input ends of the two frequency mixing units respectively, and the third power combiner is used to combine the output signals of the two frequency mixing units into one signal Then as the output signal of the mixer;

Each of the frequency mixing units includes a third transistor, a third inductor, a second feedback network, a third feed network and a third output frequency selection network, the third feed network includes a third high-pass branch and a third a low-pass branch, the signal output from the output end of the second feedback network and the signal input from the input end of the mixing unit are connected to the gate of the third transistor; the input of the third low-pass branch The input end of the third output frequency selection network is connected to the output end of the third high-pass branch, and its output end generates the output signal of the frequency mixing unit;

The first one of the mixing units works in the positive half cycle of the AC small-signal working cycle, wherein the source of the third transistor is connected to the ground signal, and the drain of the third transistor on the one hand outputs the signal connected to the third high-pass The input end of the branch and the input end of the second feedback network are connected to the signal output by the output end of the third low-pass branch on the other hand;

The second mixing unit works in the negative half cycle of the AC small-signal working cycle, wherein the drain of the third transistor is connected to the ground signal, and the source of the third transistor on the one hand outputs the signal connected to the third high-pass The input end of the branch and the input end of the second feedback network are connected to the signal output by the output end of the third low-pass branch on the other hand;

，设置所述第三输出选频网络和第二反馈网络的工作频率等于

，

为所述混频器的本振信号角频率。In each of the mixing units, the parasitic capacitance of the third transistor below the threshold voltage and the third inductance are connected in series or in parallel to form a resonance frequency selection network, and the capacitance value C3 of the parasitic capacitance of the _third transistor and the inductance value of the third inductance are set. L ₃ is satisfied

, set the operating frequency of the third output frequency selection network and the second feedback network equal to

,

is the angular frequency of the local oscillator signal of the mixer.

Specifically, the first feedback network includes a variable capacitor, a fourth inductor and a fifth inductor, and the fourth inductor and the fifth inductor are connected in series with the variable capacitor in parallel with the input terminal and the output of the first feedback network Between the terminals, the series point of the fourth inductor and the fifth inductor is grounded; the capacitance value of the variable capacitor changes with the change of the external physical quantity;

The second feedback network includes a first capacitor, a ninth inductor and a tenth inductor, and the ninth inductor and the tenth inductor are connected in series with the first capacitor and are connected in parallel between the input end and the output end of the second feedback network , the series point of the ninth inductor and the tenth inductor is grounded; the capacitance value of the first capacitor is a fixed value.

Specifically, the first feedback network includes a variable inductor, a second capacitor and a third capacitor, and the second capacitor and the third capacitor are connected in series with the variable inductor in parallel and connected to the input end of the first feedback network and the output terminal, the series point of the second capacitor and the third capacitor is grounded; the inductance value of the variable inductor changes with the change of the external physical quantity;

The second feedback network includes a sixth inductor, a sixth capacitor and a seventh capacitor, and the sixth capacitor and the seventh capacitor are connected in parallel with the sixth inductor in parallel between the input end and the output end of the second feedback network , the series point of the sixth capacitor and the seventh capacitor is grounded; the inductance value of the sixth inductor is a fixed value.

Specifically, the first low-pass branch, the second low-pass branch and the third low-pass branch have the same structure, the first low-pass branch includes a seventh inductor and a fourth capacitor, and one end of the seventh inductor It is used as the input end of the first low-pass branch and is grounded after passing through the fourth capacitor, and the other end is used as the output end of the first low-pass branch;

The first high-pass branch, the second high-pass branch and the third high-pass branch have the same structure, the first high-pass branch includes an eighth inductance and a fifth capacitor, and one end of the fifth capacitor serves as the first high-pass branch The input end of the circuit, the other end of which serves as the output end of the first high-pass branch and is grounded after passing through the eighth inductor.

The beneficial effects of the present invention are:

First of all, the invention can directly use AC small signal to drive the microwave device to work, and complete the pickup and transmission of information, which solves the limited problem caused by the need for DC power drive in the traditional information transmission system, and can be widely used in various occasions.

Secondly, the present invention uses the first feedback network to follow the change of the external physical quantity, thereby collecting the change information of the external physical quantity, so that the oscillator realizes the information pickup function.

Furthermore, the present invention provides six schemes for forming a resonant frequency selection network with transistors and inductors, and three schemes for working in the positive half cycle, negative half cycle and full cycle of the AC small signal, and gives the feedback network. The two solutions make the present invention flexible in application and wide in scope.

Finally, the present invention does not have strict requirements on the size of the driving voltage. Even if the power frequency driving voltage is small, or the power frequency voltage amplitude used as a bias is higher than the threshold voltage of the transistor, the information transmission system proposed by the present invention can work normally. .

Description of drawings

A better understanding of the following description of various embodiments of the present invention is facilitated by the following drawings, which schematically illustrate the main features of some embodiments of the present invention. These figures and examples provide some embodiments of the invention in a non-limiting, non-exhaustive manner.

FIG. 1 is a structural block diagram of an information transmission system directly driven by an AC small signal proposed by the present invention.

Figure 2 is a time-varying capacitance/voltage curve during transistor amplification. Among them, A is the power frequency bias voltage, B is the time-varying characteristic of the gate-source capacitance of the transistor in the positive half-cycle operation, C is the time-varying characteristic of the transistor gate-source capacitance in the negative half-cycle operation, and D is the drain-source capacitance of the transistor in the positive half-cycle operation Time-varying characteristics, E is the time-varying characteristic of the drain-source capacitance of the transistor during negative half-cycle operation.

FIG. 3 is a schematic structural diagram of a resonant frequency selection network formed in parallel with the gate-drain capacitance of the first transistor and the first inductance in the oscillator, and a positive power frequency cycle power frequency direct drive oscillator based on the first feedback network of the first structure. .

FIG. 4 is a schematic structural diagram of a resonant frequency selection network formed in parallel with the gate-drain capacitance of the first transistor and the first inductance in the oscillator, and a negative power frequency cycle power frequency direct drive oscillator based on the first feedback network of the first structure. .

5 is a schematic structural diagram of a resonant frequency selection network formed by paralleling the gate-drain capacitance of the first transistor and the first inductance in the oscillator, and realizing a full power frequency cycle power frequency direct drive oscillator based on the first feedback network of the first structure .

6 is a schematic diagram of the structure of the amplifier in which the gate-source capacitance of the second transistor and the second inductor are connected in parallel to form a resonant frequency selection network to directly drive the amplifier with a positive power frequency cycle.

7 is a schematic diagram of the structure of the amplifier in which the gate-source capacitance of the second transistor and the second inductor are connected in parallel to form a resonant frequency selection network to directly drive the amplifier with a negative power frequency cycle.

8 is a schematic diagram of the structure of the amplifier in which the gate-source capacitance of the second transistor and the second inductance are connected in parallel to form a resonant frequency selection network to realize the full power frequency cycle power frequency direct drive amplifier.

Fig. 9 shows the parallel connection of the drain-source capacitance of the third transistor and the third inductor to form a resonant frequency selection network in the mixer, and based on the second feedback network of the second structure to realize the direct driving of the mixer with positive power frequency cycle power frequency Schematic.

Fig. 10 shows the parallel connection of the drain-source capacitance of the third transistor and the third inductor to form a resonant frequency selection network in the mixer, and the second feedback network based on the second structure realizes the negative power frequency cycle power frequency directly drives the mixer Schematic.

Fig. 11 shows the parallel connection of the drain-source capacitance of the third transistor and the third inductor in the mixer to form a resonant frequency selection network, and based on the second feedback network of the second structure to realize the full power frequency cycle power frequency directly driving the mixer Schematic.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

As shown in FIG. 1, the information transmission system proposed by the present invention includes an AC power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network , wherein the AC power supply line is used to provide the AC small signal to drive the oscillator, amplifier and mixer. The frequency of the AC small signal used in the present invention requires that its frequency be less than one tenth of the transmission frequency of the system antenna. For example, a power frequency of 50 Hz can be used. signal or other suitable signal as the drive input. The oscillator is used to generate an output signal containing external physical quantity change information and transmit it through the first transmitting antenna, the first receiving antenna receives the signal transmitted by the first transmitting antenna and sends it to the amplifier for amplification, and the mixer receives the amplified signal by the amplifier. The signal is mixed to generate a signal that meets the output frequency requirements, and then is transmitted by the second transmitting antenna. The second receiving antenna receives the signal transmitted by the second transmitting antenna and sends it to the demodulation network to complete the demodulation of the information.

The overall working process of the present invention is as follows: the change of the external information causes the change of the resonant frequency of the first feedback network in the oscillator, so that the change information of the external physical quantity is loaded on the frequency of the electromagnetic wave output by the oscillator, and the oscillator unit completes the information transmission. Loading, the electromagnetic wave loaded with information is output by the oscillator and transmitted into the space through the first transmitting antenna, and the first receiving antenna receives the electromagnetic wave sent by the first transmitting antenna and amplifies it through the amplifier. For frequency conversion and relay, the signal amplified by the amplifier enters the mixer for frequency mixing to obtain the frequency required by the subsequent stage, and the output electromagnetic wave signal after frequency conversion by the mixer is transmitted through the second transmitting antenna. The second receiving antenna receives the electromagnetic wave sent by the second transmitting antenna and sends it to the demodulation network to complete the demodulation of the information.

为晶体管参量放大结构输入信号的角频率，

为泵浦信号即交流小信号的角频率，

是角频率为

）的谐波分量流入晶体管的功率，m和n分别为晶体管参量放大结构输出信号和泵浦信号的谐波次数。The microwave devices involved in the present invention are all driven by AC small signals, and realize oscillators, amplifiers and mixers based on parametric amplification of transistors, wherein the transistors are transistors that can work in the radio frequency microwave frequency band, such as field effect transistors or other types of transistors. of transistors that meet the conditions. The present invention uses transistors to achieve parametric amplification. The difference between the present invention and existing transistors is that the pumping frequency of the existing parametric amplifier is about twice the frequency of the input signal of the transistor parametric amplification structure, while the pumping frequency of the present invention is greatly reduced. For example, the power frequency of 50Hz can drive the transistor to amplify. In fact, for a nonlinear device, without considering the loss, when input power at some specific frequencies, the input power will be transferred to other newly generated frequency points after nonlinear transformation, that is, all frequency points. The total input power and the total output power at the point are conserved. In parametric amplifiers, this relationship is determined by the Menley-Lowe formula (Equations 1a and 1b), where

is the angular frequency of the input signal of the transistor parametric amplifier structure,

is the angular frequency of the pump signal, that is, the AC small signal,

is the angular frequency of

) of the harmonic components of the power flowing into the transistor, m and n are the harmonic orders of the output signal and the pump signal of the parametric amplifier structure of the transistor, respectively.

（1a）

(1a)

（1b）

(1b)

，这样将使得电路在信号频率

附近有增益，从而利用晶体管的非线性电容在工频偏置条件下实现参量放大。Taking the amplifier as an example, the strong nonlinear capacitance of the second transistor below the threshold voltage, that is, the parasitic capacitance of the transistor (including the gate-drain capacitance C _DG , the gate-source capacitance C _GS , and the drain-source capacitance C _DS ) and the second inductance form resonance frequency selection. network, and make the capacitance value C ₂ of the parasitic capacitance of the second transistor and the inductance value L ₂ of the second inductance satisfy

, which will make the circuit at the signal frequency

There is a gain nearby, so that parametric amplification can be achieved under the power frequency bias condition using the nonlinear capacitance of the transistor.

，从而实现参量放大。混频器利用阈值电压以下第三晶体管的寄生电容与第三电感串联或并联构成谐振选频网络，设置第三晶体管寄生电容的容值C₃和第三电感的电感值L₃满足

实现参量放大。The same is true for mixers and oscillators. The oscillator uses the parasitic capacitance of the first transistor below the threshold voltage and the first inductance in series or in parallel to form a resonant frequency selection network, and set the capacitance _C1 of the parasitic capacitance of the first transistor and the first inductance. _The inductance value L1 satisfies

, so as to achieve parametric amplification. The mixer uses the parasitic capacitance of the third transistor below the threshold voltage and the third inductance in series or in parallel to form a resonant frequency selection network, and the capacitance value C3 of the parasitic capacitance of the _third transistor and the inductance value L3 of the _third inductance are set to satisfy

To achieve parametric amplification.

The parasitic capacitance of the transistor includes the gate-drain capacitance C _DG , the gate-source capacitance C _GS , and the drain-source capacitance C _DS . As shown in Figure 3-5, the gate-drain capacitance C _DG of the first transistor of the oscillator is connected in parallel with the first inductance A schematic diagram of a resonant frequency selection network is formed. At this time, the two ends of the first inductor are respectively connected to the gate and the drain of the first transistor. In addition, the gate-drain capacitance C _DG of the first transistor of the oscillator can also be connected in series with the first inductor to form a resonant frequency selection network. At this time, the drain of the transistor is grounded or connected to the first high-pass branch after passing through the first inductor. The input end, the output end of the first low-pass branch, and the input end of the first feedback network, the series structure is not shown.

As shown in Figure 6-8, a schematic diagram of the resonant frequency selection network is formed by connecting the gate-source capacitance C _GS of the second transistor of the amplifier in parallel with the second inductor. At this time, the two ends of the second inductor are respectively connected to the gate of the second transistor. pole and drain. In addition, the gate-source capacitance C _GS of the second transistor of the amplifier can also be connected in series with the second inductor to form a resonant frequency selection network. At this time, the gate of the second transistor is connected to the first input frequency selection network through the second inductor. output.

As shown in Figure 9-11, a schematic diagram of a resonant frequency selection network is formed by connecting the drain-source capacitance C _DS of the third transistor of the mixer in parallel with the third inductor. At this time, the two ends of the third inductor are respectively connected to the third transistor. gate and drain. In addition, the drain-source capacitance C _DS of the third transistor of the mixer can be connected in series with the third inductor to form a resonant frequency selection network. At this time, the source of the transistor is grounded or connected to the third high-pass branch after passing through the third inductor. , the output of the third low-pass branch and the input of the second feedback network.

The connection methods of transistors and inductors in oscillators, amplifiers, and mixers can be the same or different, and they can be interchanged with each other. For example, the first transistor and first inductor of the oscillator use the amplifier as shown in Figure 6-8. The second transistor and the second inductor are connected in such a way that the gate-source capacitance C _GS of the first transistor and the first inductor form a resonant frequency selection network, as long as the parasitic capacitance of the transistor and the inductor are connected in series or in parallel to form a resonant frequency selection network. The traditional transistor-based microwave device for amplification needs DC power supply, but the present invention can drive the microwave device by using AC small signal, which solves the problem of energy loss in the traditional information transmission system.

A single transistor can be used to amplify in the half cycle of the AC small signal (including the positive half cycle and the negative half cycle), and two transistors can be used to achieve amplification in the full cycle. The positive half cycle, negative half cycle and full cycle For the three cases of the period, the AC small signal in the embodiment uses a 50Hz power frequency signal as an example for description.

When the information transmission system works in the positive half cycle, the oscillator adopts the structure shown in Figure 3, the amplifier adopts the structure shown in Figure 6, and the mixer adopts the structure shown in Figure 9. The common point is that the source of the transistor is grounded and the drain Connect the feeder network. Driven by a sinusoidal bias voltage as shown by A in Figure 2, when the bias voltage V _DS ≤ V _t , where V _t is the transistor threshold voltage, the capacitance/voltage characteristic between the drain and gate of the transistor at this time As shown in B in Figure 2, the capacitance/voltage characteristic between the drain and source of the transistor is shown in D in Figure 2. It can be seen that in the positive half cycle of the bias voltage, the gate-drain capacitance C _DG and the gate-source capacitance C of the transistor _{Both GS} and the drain-source capacitance C _DS show strong nonlinear changes. Therefore, the circuits shown in Figures 3, 6, and 9 can be amplified and operated within the power frequency cycle shown by B and D in Figure 2, which is close to the positive half cycle. Therefore, the information transmission system shown in Figure 1 can operate in the positive half cycle of the power frequency cycle. Work.

When the information transmission system works in the negative half cycle, the oscillator adopts the structure shown in Figure 4, the amplifier adopts the structure shown in Figure 7, and the mixer adopts the structure shown in Figure 10. The common point is that the drain of the transistor is grounded, and the source is grounded. Connect the feeder network. Driven by a sinusoidal bias voltage as shown by A in Figure 2, when the bias voltage V _DS ≤ V _t , where V _t is the transistor threshold voltage, the capacitance/voltage characteristic between the drain and gate of the transistor at this time As shown in C in Figure 2, the capacitance/voltage characteristic between the drain and source of the transistor is shown in E in Figure 2. It can be seen that in the negative half cycle of the bias voltage, the gate-drain capacitance C _DG and the gate-source capacitance C of the transistor _{Both GS} and the drain-source capacitance C _DS show strong nonlinear changes. Therefore, the circuits shown in Figures 4, 7, and 10 can be amplified and operated within the power frequency cycle shown by C and E in Figure 2, which is close to the negative half cycle. Therefore, the information transmission system shown in Figure 1 can operate in the negative half cycle of the power frequency cycle. Work.

When the information transmission system works in a full cycle, the oscillator adopts the structure shown in Figure 5. The oscillator includes an oscillating unit that works in the positive half cycle of the power frequency cycle and an oscillating unit that works in the negative half cycle of the power frequency cycle. After the first power combiner combines the output signals of the two oscillating units, an oscillator output signal that operates in a full cycle is obtained. The same is true for the amplifier and the mixer. The amplifier adopts the structure shown in Figure 8, and the mixer adopts the structure shown in Figure 11. It should be noted that when V _DS ≥ V _t , the transistors for parametric amplification in the circuits shown in Figures 5, 8, and 11 have the same circuit characteristics as the transistors for reference amplification in traditional circuits, which greatly improves the performance of the parametric amplification circuit. Dynamic Range.

The working principles of oscillators, amplifiers, and mixers are described below.

The main function of the oscillator is to complete the loading of information. The working principle of the oscillator is: at the moment of power-on, the instantaneous current and the thermal noise current existing in the circuit contain rich harmonic components. After the frequency selection and coupling of the first feedback network It is sent to the gate of the first transistor for amplification, and the amplified frequency component is selected by the first feedback network and coupled to the gate of the first transistor for re-amplification. Due to the nonlinearity of the transistor, this process will not continue forever. , and finally tends to a steady state. The stabilized frequency signal can only flow out from the first high-pass branch of the first feeding network through the first feeding network, and the signal flowing out from the first high-pass branch is sent out after impedance matching by the first output frequency selection network. In the present invention, the resonance angular frequency of the first feedback network is related to the change of the external physical quantity, so that the output signal of the oscillator contains the change information of the external physical quantity. The frequency signal, as shown in Figure 3-5, uses a variable capacitor to follow the change of the external physical information. When the variable capacitor changes with the change of the external physical information, the frequency signal output by the first feedback network will occur. Corresponding changes to complete the information acquisition. In some embodiments, the feedback network structure shown in FIGS. 9-11 may also be used, and the inductance in it may be changed to a variable inductance, so that the variable inductance can follow the changes of the external physical information.

The main function of the amplifier is to complete the amplification of the signal. The working principle of the amplifier: the input signal of the amplifier is fed into the gate of the second transistor after impedance matching in the working frequency band through the first input frequency selection network (ie the gate frequency selection network). The input small signal is amplified in the second transistor, and the amplified signal can only flow out from the second high-pass branch of the second feed network through the second feeding network, and the signal flowing out from the second high-pass branch is output by the second The frequency selection network (ie, the drain frequency selection network or the source frequency selection network) is impedance matched and sent out to the amplifier, and the power frequency drive of the amplifier is fed into the second transistor through the second low-pass branch of the second feeding network.

The main function of the mixer is to complete the frequency conversion relay transmission. The working principle of the mixer: at the moment of power-on, the instantaneous current and the thermal noise current existing in the circuit contain rich harmonic components. It is coupled to the gate of the third transistor for amplification, and the amplified frequency components are selected by the second feedback network and coupled to the gate of the third transistor for re-amplification. Due to the nonlinearity of the transistor, this process will not continue. Going down, the local oscillator signal of the mixer is formed when it finally tends to a stable state. On the other hand, the RF signal input by the mixer is input to the gate of the third transistor through the second input matching network, and after mixing with the local oscillator signal returned by the second feedback network, the required intermediate frequency is obtained at the drain of the third transistor Signal. The intermediate frequency signal can only flow out from the third high-pass branch of the third feed network through the third feed network. The signal flowing out from the third high-pass branch is impedance matched by the third output frequency selection network and sent to the mixer. The power frequency drive of the mixer (50Hz power frequency signal in this embodiment) is fed into the third transistor from the third low-pass branch of the third feeding network.

To sum up, the present invention provides the resonant frequency selection network composed of transistor gate-drain capacitance, gate-source capacitance, drain-source capacitance and inductor in parallel in microwave devices (including oscillators, amplifiers, and mixers) through several embodiments. Three structures, as well as three structures of transistor gate-drain capacitance, gate-source capacitance, drain-source capacitance and inductance in series to form a resonant frequency selective network, and two implementation structures for realizing the feedback network, as well as the information transmission system in the positive frequency of the power frequency are also given. There are three structures that work in half cycle, negative half cycle and full power frequency cycle. The six connection structures of parasitic capacitance and inductance of transistors can be arbitrarily arranged and combined with the two realization structures of feedback network, and can also be combined with microwave devices in positive half cycle of power frequency, The three structures operating in the negative half cycle and the full power frequency period can be arbitrarily arranged and combined, so that the information transmission system proposed by the present invention can be directly driven by the power frequency, and can be widely used in various occasions.

In addition, the present invention does not have strict requirements on the size of the driving voltage. Taking the structure of FIG. 3 as an example, in the working process according to the example shown in FIG. 3, the present invention finds that when the size of the power frequency driving voltage is only 0.1V The circuit can also be amplified, and the voltage of 0.1V can be easily obtained on the power grid, which provides great convenience for the application of this type of information pickup circuit. Through this embodiment, the present invention also finds that even if the amplitude of the power frequency voltage used as a bias is higher than the threshold voltage of the transistor, the transistor can also achieve amplification. The normal amplification region of the bias voltage variation enables the embodiment of FIG. 3 to operate over a wide range of bias voltage amplitudes.

Those of ordinary skill in the art will appreciate that the embodiments described herein are intended to assist readers in understanding the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Various modifications and variations of the present invention are possible for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims (9)

1. The information transmission system is characterized by comprising an alternating current power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network, wherein the information transmission system works in a half period of the working period of an alternating current small signal, and the frequency of the alternating current small signal is less than one tenth of the transmitting frequency of the first transmitting antenna or the second transmitting antenna; the AC supply line provides the AC small signal for driving the oscillator, amplifier and mixer; the oscillator is used for generating an output signal containing external physical quantity change information and transmitting the output signal through the first transmitting antenna, the first receiving antenna receives a signal transmitted by the first transmitting antenna and transmits the signal to the amplifier for amplification, the mixer receives the signal amplified by the amplifier and performs frequency mixing to generate a signal meeting the output frequency requirement, and then the signal is transmitted through the second transmitting antenna, and the second receiving antenna receives the signal transmitted by the second transmitting antenna and transmits the signal to the demodulation network to complete information demodulation;

the oscillator comprises a first transistor, a first inductor, a first feedback network, a first feed network and a first output frequency selection network, wherein a parasitic capacitor of the first transistor below a threshold voltage is connected with the first inductor in series or in parallel to form a resonant frequency selection network, and a capacitance value C of the parasitic capacitor of the first transistor is set₁And inductance L of the first inductor₁Satisfy the requirement of

，

Setting the operating frequency of the first output frequency-selective network equal to the initial resonant angular frequency of the first feedback network

(ii) a The first feed network comprises a first high-pass branch and a first low-pass branch, one end of a drain electrode and a source electrode of the first transistor is connected with the ground level, and the other end of the first feed network outputs signals which are connected with the input end of the first feedback network and the input end of the first high-pass branch on one hand and signals output by the output end of the first low-pass branch on the other hand; the signal output by the output end of the first feedback network is connected with the grid electrode of the transistor; the input end of the first low-pass branch is connected with the alternating current small signal; the input end of the first output frequency-selecting network is connected with the output end of the first high-pass branch, and the output end of the first output frequency-selecting network generates an output signal of the oscillator; the resonance angular frequency of the first feedback network is related to the change of the external physical quantity, and the output signal of the oscillator contains the change information of the external physical quantity;

the amplifier comprises a second transistor, a second inductor, a first input frequency selection network, a second feed network and a second output frequency selection network, wherein the parasitic capacitance of the second transistor below a threshold voltage is connected with the second inductor in series or in parallel to form a resonant frequency selection network, and the capacitance C of the parasitic capacitance of the second transistor is set₂And inductance L of the second inductor₂Satisfy the requirement of

Setting the operating frequency of the first input frequency-selective network and the second output frequency-selective network equal to

，

Is the input signal angular frequency of the amplifier; the signal received by the first receiving antenna is used as an input signal of the amplifier and is connected to the input end of the first input frequency-selecting network, and the signal output by the output end of the first input frequency-selecting network is connected with the grid electrode of the second transistor; the second feed network comprises a second high-pass branch and a second high-pass branchOne end of the drain electrode and one end of the source electrode of the second transistor are connected with a ground signal, and the other end of the drain electrode and the source electrode of the second transistor are connected with an input end of the second high-pass branch on one hand and a signal output by an output end of the second low-pass branch on the other hand; the input end of the second low-pass branch is connected with the alternating current small signal, the output end of the second high-pass branch is connected with the input end of the second output frequency-selecting network, and the output end of the second output frequency-selecting network generates the output signal of the amplifier;

the frequency mixer comprises a third transistor, a third inductor, a second input frequency selection network, a second feedback network, a third feed network and a third output frequency selection network, wherein the parasitic capacitance of the third transistor below a threshold voltage is connected with the third inductor in series or in parallel to form a resonant frequency selection network, and the capacitance C of the parasitic capacitance of the third transistor is set₃And inductance L of the third inductor₃Satisfy the requirement of

Setting the operating frequency of the third output frequency-selective network and the second feedback network to be equal to

，

The local oscillation signal angular frequency of the frequency mixer is obtained; the input end of the second input frequency-selecting network is connected with the output signal of the amplifier, the signal output by the output end of the second input frequency-selecting network is connected with the grid electrode of the third transistor, and the working frequency of the second input frequency-selecting network is set to be equal to the frequency of the output signal of the amplifier; the third feed network comprises a third high-pass branch and a third low-pass branch, one of a drain electrode and a source electrode of the third transistor is connected with the ground level, and the other end of the third feed network outputs signals which are connected with the input end of the second feedback network and the input end of the third high-pass branch on the one hand and connected with the signals output by the output end of the third low-pass branch on the other hand; the signal output by the output end of the second feedback network is connected with the stationA gate of the third transistor; the input end of the third low-pass branch is connected with the alternating current small signal; the input end of the third output frequency-selecting network is connected with the output end of the third high-pass branch, and the output end of the third output frequency-selecting network generates an output signal of the frequency mixer.

2. The information transmission system directly driven by the alternating current small signal according to claim 1, wherein if the sources of the first transistor, the second transistor and the third transistor are connected to a ground signal, the information transmission system operates in a positive half period of the duty cycle of the alternating current small signal; and if the drains of the first transistor, the second transistor and the third transistor are connected with a ground signal, the information transmission system works in a negative half period of the working cycle of the alternating small signal.

3. The information transmission system directly driven by the alternating current small signals as claimed in claim 1 or 2, wherein the first feedback network comprises a variable capacitor, a fourth inductor and a fifth inductor, the fourth inductor and the fifth inductor are connected in series and then connected in parallel with the variable capacitor between the input end and the output end of the first feedback network, and the series point of the fourth inductor and the fifth inductor is grounded; the capacitance value of the variable capacitor changes along with the change of the external physical quantity;

the second feedback network comprises a first capacitor, a ninth inductor and a tenth inductor, the ninth inductor and the tenth inductor are connected in series and then are connected in parallel with the first capacitor between the input end and the output end of the second feedback network, and the series point of the ninth inductor and the tenth inductor is grounded; the capacitance value of the first capacitor is a fixed value.

4. The information transmission system directly driven by the alternating current small signals as claimed in claim 1 or 2, wherein the first feedback network comprises a variable inductor, a second capacitor and a third capacitor, the second capacitor and the third capacitor are connected in series and then connected in parallel with the variable inductor between the input end and the output end of the first feedback network, and the series connection point of the second capacitor and the third capacitor is grounded; the inductance value of the variable inductor changes along with the change of the external physical quantity;

the second feedback network comprises a sixth inductor, a sixth capacitor and a seventh capacitor, the sixth capacitor and the seventh capacitor are connected in series and then are connected in parallel with the sixth inductor between the input end and the output end of the second feedback network, and the series point of the sixth capacitor and the seventh capacitor is grounded; the inductance value of the sixth inductor is a fixed value.

5. The information transmission system directly driven by small alternating current signals according to claim 1, wherein the first low-pass branch, the second low-pass branch and the third low-pass branch have the same structure, the first low-pass branch comprises a seventh inductor and a fourth capacitor, one end of the seventh inductor is used as an input end of the first low-pass branch and is grounded through the fourth capacitor, and the other end of the seventh inductor is used as an output end of the first low-pass branch;

the first high-pass branch circuit, the second high-pass branch circuit and the third high-pass branch circuit are identical in structure, the first high-pass branch circuit comprises an eighth inductor and a fifth capacitor, one end of the fifth capacitor is used as the input end of the first high-pass branch circuit, and the other end of the fifth capacitor is used as the output end of the first high-pass branch circuit and is grounded after passing through the eighth inductor.

6. The information transmission system is characterized by comprising an alternating current power supply line, an oscillator, an amplifier, a mixer, a first transmitting antenna, a first receiving antenna, a second transmitting antenna, a second receiving antenna and a demodulation network, wherein the information transmission system works in the whole period of the working period of the alternating current small signal, and the frequency of the alternating current small signal is less than one tenth of the transmitting frequency of the first transmitting antenna or the second transmitting antenna;

the AC supply line provides the AC small signal for driving the oscillator, amplifier and mixer; the oscillator is used for generating an output signal containing external physical quantity change information and transmitting the output signal through the first transmitting antenna, the first receiving antenna receives a signal transmitted by the first transmitting antenna and transmits the signal to the amplifier for amplification, the mixer receives the signal amplified by the amplifier and performs frequency mixing to generate a signal meeting the output frequency requirement, and then the signal is transmitted through the second transmitting antenna, and the second receiving antenna receives the signal transmitted by the second transmitting antenna and transmits the signal to the demodulation network to complete information demodulation;

the oscillator comprises two oscillation units and a first power synthesizer, wherein the first power synthesizer is used for combining output signals of the two oscillation units into one signal and then taking the signal as an output signal of the oscillator;

each oscillating unit comprises a first transistor, a first inductor, a first feedback network, a first feed network and a first output frequency-selecting network, wherein the first feed network comprises a first high-pass branch and a first low-pass branch, and the grid of the first transistor is connected with a signal output by the output end of the first feedback network; the input end of the first low-pass branch is connected with the alternating current small signal; the input end of the first output frequency-selecting network is connected with the output end of the first high-pass branch, and the output end of the first output frequency-selecting network generates an output signal of the oscillating unit;

the first oscillating unit works in the positive half period of the working period of the alternating small signal, wherein the source electrode of the first transistor is connected with a ground signal; the drain electrode of the first transistor outputs a signal which is connected with the input end of the first high-pass branch and the input end of the first feedback network on one hand, and is connected with a signal output by the output end of the first low-pass branch on the other hand;

the second oscillation unit works in the negative half period of the working period of the alternating small signal, wherein the drain electrode of the first transistor is connected with a ground signal; the source electrode of the first transistor outputs a signal which is connected with the input end of the first high-pass branch and the input end of the first feedback network on one hand, and is connected with a signal output by the output end of the first low-pass branch on the other hand;

in each oscillation unit, a parasitic capacitor of a first transistor below a threshold voltage and a first inductor are connected in series or in parallel to form a resonant frequency selection network, and a capacitance value C of the parasitic capacitor of the first transistor is set₁And inductance L of the first inductor₁Satisfy the requirement of

Setting the operating frequency of the first output frequency-selective network equal to

，

The initial resonance angular frequency of the first feedback network in the two oscillation units is the same, so that the resonance angular frequency of the first feedback network in the two oscillation units is related to the change of the same external physical quantity, and the output signal of the oscillator contains the change information of the external physical quantity;

the amplifier comprises a first power divider, a second power combiner and two amplifying units, wherein the first power divider is used for dividing signals received by the first receiving antenna into two signals and then respectively connecting the two signals to the input ends of the two amplifying units, and the second power combiner is used for combining the output signals of the two amplifying units into one signal and then using the signal as the output signal of the amplifier;

each amplifying unit comprises a second transistor, a second inductor, a first input frequency-selecting network, a second feed network and a second output frequency-selecting network, wherein the input end of the first input frequency-selecting network is used as the input end of the amplifying unit, and a signal output by the output end of the first input frequency-selecting network is connected with the grid electrode of the second transistor; the second feed network comprises a second high-pass branch and a second low-pass branch, the input end of the second low-pass branch is connected with the alternating current small signal, the output end of the second high-pass branch is connected with the input end of the second output frequency-selecting network, and the output end of the second output frequency-selecting network outputs the output signal of the amplifying unit;

the first amplifying unit works in the positive half period of the working period of the alternating small signal, wherein the source electrode of the second transistor is connected with a ground signal, and the drain electrode of the second transistor is connected with the signal output by the output end of the second high-pass branch on one hand and the signal output by the output end of the second low-pass branch on the other hand;

the second amplifying unit works in the negative half period of the working cycle of the alternating current small signal, wherein the drain electrode of the second transistor is connected with a ground signal, and the source electrode of the second transistor is connected with the output signal of the second high-pass branch on one hand and the signal output by the output end of the second low-pass branch on the other hand;

in each amplifying unit, a parasitic capacitor of a second transistor below a threshold voltage is connected in series or in parallel with a second inductor to form a resonant frequency-selecting network, and a capacitance value C of the parasitic capacitor of the second transistor is set₂And inductance L of the second inductor₂Satisfy the requirement of

Setting the operating frequency of the first input frequency-selective network and the second output frequency-selective network equal to

，

Receiving an angular frequency of a signal for the first receive antenna;

the mixer comprises a second input frequency-selecting network, a second power divider, a third power synthesizer and two mixing units, wherein the input end of the second input frequency-selecting network is connected with the output signal of the amplifier, the output end of the second input frequency-selecting network is connected with the input end of the second power divider, and the working frequency of the second input frequency-selecting network is set to be as close to the frequency of the output signal of the amplifier as possible; the second power divider is configured to divide a signal output by the second input frequency-selective network into two signals and then respectively connect the two signals to input ends of the two frequency mixing units, and the third power combiner is configured to combine output signals of the two frequency mixing units into one signal and then use the signal as an output signal of the frequency mixer;

each frequency mixing unit comprises a third transistor, a third inductor, a second feedback network, a third feed network and a third output frequency selection network, wherein the third feed network comprises a third high-pass branch and a third low-pass branch, and a signal output by an output end of the second feedback network and a signal input by an input end of the frequency mixing unit are connected to a grid electrode of the third transistor; the input end of the third low-pass branch is connected with the alternating current small signal; the input end of the third output frequency-selecting network is connected with the output end of the third high-pass branch, and the output end of the third output frequency-selecting network generates an output signal of the frequency mixing unit;

the first frequency mixing unit works in the positive half period of the working period of the alternating current small signal, wherein the source electrode of a third transistor is connected with a ground signal, and the drain electrode of the third transistor outputs a signal which is connected with the input end of the third high-pass branch and the input end of the second feedback network on one hand and is connected with a signal output by the output end of the third low-pass branch on the other hand;

the second mixing unit works in the negative half period of the working period of the alternating current small signal, wherein the drain electrode of a third transistor is connected with a ground signal, and the source electrode of the third transistor outputs a signal which is connected with the input end of the third high-pass branch and the input end of the second feedback network on one hand and is connected with a signal output by the output end of the third low-pass branch on the other hand;

in each frequency mixing unit, a parasitic capacitor of a third transistor below a threshold voltage and a third inductor are connected in series or in parallel to form a resonant frequency selection network, and a capacitance value C of the parasitic capacitor of the third transistor is set₃And inductance L of the third inductor₃Satisfy the requirement of

Setting the operating frequency of the third output frequency-selective network and the second feedback network to be equal to

，

Is the local oscillator signal angular frequency of the mixer.

7. The information transmission system directly driven by alternating current small signals is characterized in that the first feedback network comprises a variable capacitor, a fourth inductor and a fifth inductor, the fourth inductor and the fifth inductor are connected in series and then connected in parallel with the variable capacitor between the input end and the output end of the first feedback network, and the series point of the fourth inductor and the fifth inductor is grounded; the capacitance value of the variable capacitor changes along with the change of the external physical quantity;

the second feedback network comprises a first capacitor, a ninth inductor and a tenth inductor, the ninth inductor and the tenth inductor are connected in series and then connected in parallel with the first capacitor between the input end and the output end of the second feedback network, and the series point of the ninth inductor and the tenth inductor is grounded; the capacitance value of the first capacitor is a fixed value.

8. The information transmission system directly driven by alternating current small signals is characterized in that the first feedback network comprises a variable inductor, a second capacitor and a third capacitor, the second capacitor and the third capacitor are connected in series and then connected in parallel with the variable inductor between the input end and the output end of the first feedback network, and the series point of the second capacitor and the third capacitor is grounded; the inductance value of the variable inductor changes along with the change of the external physical quantity;

the second feedback network comprises a sixth inductor, a sixth capacitor and a seventh capacitor, the sixth capacitor and the seventh capacitor are connected in series and then are connected in parallel with the sixth inductor between the input end and the output end of the second feedback network, and the series point of the sixth capacitor and the seventh capacitor is grounded; the inductance value of the sixth inductor is a fixed value.

9. The information transmission system directly driven by small alternating current signals according to any one of claims 6 to 8, wherein the first low-pass branch, the second low-pass branch and the third low-pass branch have the same structure, the first low-pass branch includes a seventh inductor and a fourth capacitor, one end of the seventh inductor is used as the input end of the first low-pass branch and is grounded after passing through the fourth capacitor, and the other end of the seventh inductor is used as the output end of the first low-pass branch;

the first high-pass branch circuit, the second high-pass branch circuit and the third high-pass branch circuit are identical in structure, the first high-pass branch circuit comprises an eighth inductor and a fifth capacitor, one end of the fifth capacitor is used as the input end of the first high-pass branch circuit, and the other end of the fifth capacitor is used as the output end of the first high-pass branch circuit and is grounded after passing through the eighth inductor.

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