JP2005354242A - Wireless communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication apparatus with both ASK and QPSK functions that can stop a QPSK transmission function in the case of transmission by ASK modulation so as to share an oscillation circuit and a reference oscillator required for ASK transmission/reception and QPSK transmission/reception thereby reducing the power consumption and attaining downsizing. <P>SOLUTION: The wireless communication apparatus includes an ASK modulation circuit, a QPSK modulation circuit, the oscillation circuit, and a modulation system switching circuit, allows the switching circuit to bypass the QPSK modulation circuit in the case of carrying out ASK modulation, applies QPSK modulation to a transmission carrier and passes through the ASK modulation circuit without carrying out ASK modulation and transmits the modulated carrier in the case of QPSK modulation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  According to the present invention, short-range wireless communication can be performed by any of PSK modulation methods such as an amplitude modulation (Amplitude Shift Keying: hereinafter referred to as ASK modulation) method and a quadrature phase shift keying (hereinafter referred to as QPSK modulation) method. The present invention relates to a dual-mode wireless communication device that can be used.

  In wireless communication devices for near field communication such as road traffic information systems, ETC, and drive-through, an ASK modulation method that modulates the amplitude of a carrier wave according to an ASK data signal, an I signal (in-phase signal) according to a QPSK data signal Various modulation schemes such as a QPSK modulation scheme that modulates the phase of a carrier wave in four phases using a Q signal (quadrature signal; a signal shifted by 90 ° with respect to the in-phase signal) may be used in combination. In this case, since it is necessary to configure each of the ASK transmission / reception circuit and the QPSK transmission / reception circuit, a plurality of local oscillation circuits and reference oscillators are required as well as the respective modulation circuits. As a result, the circuit scale of the wireless communication device has increased, the number of parts has increased, and the power consumption has increased.

In this way, in a wireless communication device having an ASK transmission / reception function and a QPSK transmission / reception function, a device is proposed in which the QPSK modulator is used as a sine wave generation circuit so as to reduce the size of the entire device (patent). Reference 1).
JP 2002-289898 A

  However, the wireless communication device of Patent Document 1 uses the QPSK modulator as a sine wave generation circuit and uses it as a high-frequency signal source when performing communication by ASK modulation. Therefore, even when communication by QPSK modulation is not performed. The QPSK modulator must be operating at all times. Therefore, it is difficult to reduce power consumption.

  Further, in the wireless communication device of Patent Document 1, although it has been described up to converting a high frequency received signal into an intermediate frequency (IF) signal, how to demodulate a received signal modulated by ASK or QPSK. Is not shown. In order to demodulate these received signals, an oscillation circuit and a reference oscillator for generating a predetermined frequency signal must be further provided.

  Therefore, the present invention makes it possible to stop the PSK transmission function at the time of transmission by ASK modulation, and to reduce power consumption and miniaturization by sharing an oscillation circuit and a reference oscillator necessary for ASK transmission / reception and PSK transmission / reception. An object of the present invention is to provide a wireless communication device having an ASK transmission / reception function and a PSK transmission / reception function.

A wireless communication device according to claim 1, wherein an ASK modulation circuit that ASK modulates a transmission carrier wave using amplitude modulation data;
A PSK modulation circuit that PSK modulates a transmission carrier wave using phase modulation data;
An oscillation circuit that generates at least a transmission carrier; and
A modulation system switching circuit that receives the transmission carrier from the oscillation circuit and switches between connecting the ASK modulation circuit and the PSK modulation circuit in series or bypassing the PSK modulation circuit according to a modulation system switching signal; Have
In the case of ASK modulation, the PSK modulation circuit is bypassed by the modulation system switching circuit, the transmission carrier wave that has passed through the modulation system switching circuit is ASK modulated by the ASK modulation circuit, and transmitted as an ASK modulated wave,
When performing PSK modulation, the transmission carrier is PSK modulated by the PSK modulation circuit, and the PSK modulated PSK modulated wave is transmitted through the ASK modulation circuit without ASK modulation. .

A wireless communication device according to claim 2, wherein an ASK modulation circuit that ASK modulates a transmission carrier wave using amplitude modulation data;
A PSK modulation circuit that PSK modulates a transmission carrier wave using phase modulation data;
A reception / demodulation circuit for both ASK and PSK, which receives a modulated wave subjected to ASK modulation or PSK modulation and demodulates received data;
An oscillation circuit for generating a reference carrier frequency generated by a reference oscillator and a transmission carrier having a frequency higher than the reference frequency based on the reference frequency;
A modulation scheme switching circuit that receives the transmission carrier from the oscillation circuit and switches between supplying the transmission carrier to the PSK modulation circuit or bypassing the PSK modulation circuit according to a transmission / reception switching signal and a modulation scheme switching signal; ,
In accordance with a transmission / reception switching signal, the transmission carrier wave or PSK modulated wave from the modulation system switching circuit is switched to supply to the ASK modulation circuit or to the reception / demodulation circuit as a first local oscillation frequency signal, and A transmission / reception switching circuit for switching whether to transmit an ASK or PSK modulated wave from the ASK modulation circuit to the outside or to receive a reception signal from the outside,
At the time of transmission, when the transmission / reception switching circuit is switched to the transmission side and ASK modulation is performed, the PSK modulation circuit is bypassed by the modulation system switching circuit, and the transmission carrier wave that has passed through the modulation system switching circuit is transmitted to the ASK modulation circuit. In the case of ASK modulation and transmission as an ASK modulated wave, and in the case of PSK modulation, the transmission carrier is PSK modulated by the PSK modulation circuit, and the PSK modulated PSK modulated wave is not ASK modulated. Transmit through the ASK modulation circuit,
At the time of reception, the transmission / reception switching circuit is switched to the reception side, and the reception / demodulation circuit mixes the reception signal and the first local oscillation frequency signal to mix the reference frequency or an integral multiple thereof or one integral fraction thereof. The intermediate frequency signal is obtained, and the intermediate frequency signal is demodulated using the second local oscillation frequency signal having the same frequency as the intermediate frequency signal to obtain ASK reception data or PSK reception data.

The wireless communication device according to claim 3 is the wireless communication device according to claim 1 or 2, wherein the modulation method switching circuit is
A first changeover switch having a common terminal connected to the transmission carrier output side of the oscillation circuit and one switching terminal connected to the carrier input side of the PSK modulation circuit;
One switching terminal is connected to the output side of the PSK modulation circuit, the other switching terminal is connected to the other switching terminal of the first switching switch, and a second switching switch for outputting a carrier wave from a common terminal is provided. Features.

  According to a fourth aspect of the present invention, in the wireless communication apparatus according to any one of the first to third aspects, the operation of the PSK modulator is turned off when the PSK modulator is bypassed by the modulation method switching circuit.

  The wireless communication device according to claim 5 is the wireless communication device according to any one of claims 1 to 4, wherein the PSK modulator has a quadrature modulator, and the quadrature modulator includes transmission in-phase data and transmission quadrature data. The transmission carrier is QPSK modulated by / 4 shift QPSK transmission data.

  The wireless communication device according to claim 6 is the wireless communication device according to claim 2, wherein the oscillation circuit generates a transmission carrier wave by a phased-lock loop circuit based on the reference frequency, and the reference frequency Is equal to the difference frequency between the transmission carrier frequency and the reception carrier frequency, or is an integral multiple or a fraction of the integral of the difference frequency.

  The wireless communication device according to claim 7 is the wireless communication device according to claim 2 or 6, wherein the reception / demodulation circuit includes a quadrature demodulator, and the quadrature demodulator includes the intermediate frequency signal and the intermediate frequency signal. The quadrature demodulation is performed using the second local oscillation frequency signal formed based on the reference frequency signal so as to have the same frequency as that of π / 4 shift QPSK reception in-phase data and reception quadrature data or ASK reception data. It is characterized by that.

  The ASK / PSK dual mode wireless communication apparatus according to the present invention can stop (turn off) the PSK (QPSK) transmission function at the time of transmission by ASK modulation, and can also be an oscillation circuit required for ASK transmission / reception and PSK (QPSK) transmission / reception. Since the reference oscillator is shared, power consumption can be reduced and downsizing can be achieved.

  In addition, since ASK transmission and PSK transmission are directly modulated with the transmission data, it is not necessary to consider local leakage and image suppression required when the heterodyne method is used. Therefore, a steep characteristic is not required for the BPF for high frequency signals.

  Further, since the second local oscillation frequency signal uses the reference frequency of the oscillation circuit or a frequency obtained by multiplying it by an integral multiple or a fraction of an integer, the number of oscillation circuits for the second local oscillation frequency signal can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a wireless communication device according to the present invention. FIG. 2 is a diagram illustrating an internal configuration example of the oscillation circuit of FIG. 3 is a diagram illustrating a configuration example of a quadrature modulator for performing the QPSK modulation of FIG. 1, and FIG. 4 is a diagram illustrating a configuration example of the quadrature demodulator for performing the QPSK demodulation of FIG. In this embodiment, QPSK modulation is described as an example of phase modulation. However, the present invention can also be applied to other two-phase and eight-phase modulation.

  In FIG. 1, a radio wave is transmitted and received by an antenna 1 and a band pass filter (hereinafter referred to as BPF) for a carrier wave.

  The ASK modulation circuit 10 receives a transmission carrier wave having a transmission carrier frequency f1, modulates it with ASK transmission data Atx, and outputs it. In this example, the transmission carrier frequency f1 is 5.815 to 5.845 GHz, and for example, 5.815 GHz is used.

  In the ASK modulation circuit 10, the input transmission carrier wave is adjusted by the variable attenuator 12 and attenuated to a desired state. The ASK modulator 11 modulates the amplitude of the transmission carrier wave from the variable attenuator 12 according to the ASK transmission data Atx by using an amplitude modulation driver circuit 13 and a low-pass filter (hereinafter, LPF) 14. The ASK modulated wave amplitude-modulated by the ASK modulator 11 is amplified by an amplifier (hereinafter referred to as AMP) 15 and output.

  As the ASK transmission data Atx, for example, split-phase encoded 2.048 Mbaud data is used. However, when transmission is performed with π / 4 shift QPSK, the gain of the ASK modulator 11 is set to a constant value, for example, the maximum so that the ASK modulation circuit 10 functions as an amplifier circuit. This constant value setting means that the PSK modulated wave is passed through the ASK modulation circuit without ASK modulation. For example, the driver circuit 13 sets the ASK transmission data Atx to the H (high) level. .

  The QPSK modulation circuit 20 receives a transmission carrier having a transmission carrier frequency f1, and quadrature modulates the transmission carrier with QPSK transmission data in the π / 4 shift format; transmission in-phase data Itx and transmission quadrature data Qtx and outputs the result.

  In the QPSK modulation circuit 20, the quadrature modulator 21 performs quadrature modulation on the input transmission carrier with the transmission in-phase data Itx and the transmission quadrature data Qtx, and amplifies it with the AMP 22 and outputs it. The LPFs 23 and 24 remove noise included in the transmission in-phase data Itx and the transmission quadrature data Qtx. Note that the circuit configuration can be simplified by not using the AMP 22. Even in this case, since the QPSK modulated QPSK modulated wave is amplified by the AMP 15 provided in the ASK modulation circuit 10, there is no problem even if the AMP 22 is omitted.

  The transmission in-phase data Itx and the transmission quadrature data Qtx are data in the π / 4 shift format, for example, 2.048 Mbaud data.

  The internal configuration of the quadrature modulator 21 is shown in FIG. As shown in FIG. 3, the input transmission carrier wave is mixed with the transmission in-phase data Itx by the mixer 211. In addition, the mixer 212 mixes the transmission carrier whose phase is shifted by the 90 ° phase shift circuit with the transmission quadrature data Qtx. The outputs from the mixers 211 and 212 are added by the adder 214 and output as a quadrature modulated QPSK modulated wave.

  The QPSK modulation circuit 20 is not used when transmitted by ASK modulation. Since this state is given by the modulation system switching signal QPSK / ASK, it is preferable to stop the operation of the QPSK modulation circuit 20 at the time of transmission by ASK modulation. Specifically, it is appropriate to turn off the power supply of the QPSK modulation circuit 20.

  The oscillation circuit 30 generates a transmission carrier wave having a transmission carrier frequency f1. This transmission carrier wave also serves as a first local oscillation frequency signal during reception. The oscillation circuit 30 generates a reference signal having a reference frequency f0. The reference frequency f0 is a second local oscillation frequency signal for demodulating the received signal after being multiplied or lowered (that is, divided) or as it is.

  The internal configuration of the oscillation circuit 30 is shown in FIG. In FIG. 2, the reference oscillator 31 oscillates a highly accurate reference frequency f0. For example, a temperature compensated crystal oscillator (TCXO) is used, and the frequency f0 is 20 MHz in this example. This 20 MHz reference frequency f0 is a reference for various frequency signals of the present invention. Based on this reference frequency f0, a transmission carrier frequency f1 is generated by a phase-locked loop (PLL) comprising a voltage controlled oscillator 32, a phase comparator 33, and a loop filter (eg, LPF) 34. The reference frequency f0 is multiplied and divided by a dedicated circuit and used as various operation clocks of the wireless communication apparatus of the present invention.

  The modulation system changeover circuit 40 includes a first changeover switch 41 and a second changeover switch 42 that are switched according to whether transmission is performed by ASK modulation, transmission by QPSK modulation, and transmission or reception. In this sense, the modulation system switching circuit 40 may be referred to as a transmission / reception / modulation system switching circuit. When ASK modulation is performed, the first changeover switch 41 and the second changeover switch 42 are switched to bypass the QPSK modulation circuit 20, and the transmission carrier wave that has passed through the first changeover switch 41 and the second changeover switch 42 is transferred to the ASK modulation circuit 10. To ASK-modulate and transmit as an ASK modulated wave. In the case of QPSK modulation, the first changeover switch 41 and the second changeover switch 42 are switched to the opposite side, the transmission carrier is QPSK modulated by the QPSK modulation circuit 20, and the ASK modulation circuit 10 does not perform the ASK modulation. Pass through and transmit as QPSK modulated wave.

  The first changeover switch 41 has a common terminal c connected to the output terminal of the amplifier 44 that amplifies the transmission carrier wave from the oscillation circuit 30, and one changeover terminal a connected to the carrier input side of the QPSK modulation circuit 20. . The second changeover switch 42 has one changeover terminal a connected to the output side of the QPSK modulation circuit 20, the other changeover terminal b connected to the other changeover terminal b of the first changeover switch 41, and the common terminal c to the QPSK cover. A modulated wave is output.

  The first changeover switch 41 switches between the modulation system changeover signal QPSK / ASK and the transmission / reception changeover signal Tx / Rx using the logic circuit 43 (AND circuit in this example). In this embodiment, the modulation system switching signal QPSK / ASK is high (H) level during QPSK modulation and low (L) level during ASK modulation, and the transmission / reception switching signal Tx / Rx is H level during transmission and L during reception. Is a level.

  Therefore, when transmitting by QPSK modulation, the first and second changeover switches 41 and 42 are both switched to one switching contact a, and the transmission carrier is subjected to π / 4 shift QPSK modulation by the QPSK modulation circuit 20. At the time of reception or ASK transmission, both the first changeover switches 41 and 42 are switched to the other changeover contact b, and the QPSK modulation circuit 20 is bypassed.

  In FIG. 1, the operation or non-operation of the QPSK modulation circuit 20 is controlled by the output of the logic circuit 43. However, when the transmission / reception is frequently switched, the modulation method is not the output of the logic circuit 43. It is preferable to control the operation or non-operation only by the switching signal QPSK / ASK.

  The transmission / reception switching circuit 50 includes a third switching switch 51 and a fourth switching switch 52 that are switched by a transmission / reception switching signal Tx / Rx. The third and fourth changeover switches 51 and 52 are switched to the ASK modulation circuit 10 side during transmission, and are switched to the reception / demodulation circuit 60 side during reception.

  The ASK / QPSK shared reception / demodulation circuit 60 receives an external QPSK modulated or ASK modulated reception signal, and demodulates the QPSK reception data or ASK reception data. The externally received carrier frequency f2 is 5.775 to 5.805 GHz in this example, and for example, 5.775 GHz is used.

  The mixer 62 includes a modulated wave that is ASK or QPSK modulated and that is input through the low noise amplifier 61 and a first local oscillation frequency signal (that is, a transmission carrier frequency) that is input via the third changeover switch 51. ). The output of the mixer 62 is filtered by the BPF 63 to obtain an intermediate frequency signal IF. This intermediate frequency signal IF is a difference frequency (= 40 MHz) between the reception carrier frequency f2 (= 5.775 GHz) and the first local oscillation frequency signal (= 5.815 GHz).

  The quadrature demodulator 65 receives the intermediate frequency signal IF passed through the variable gain amplifier 64 and the second local oscillation frequency signal (= 40 MHz) obtained by multiplying the reference frequency f0 (= 20 MHz) from the oscillation circuit 30 by the multiplier 66. The received data included in the intermediate frequency signal IF is demodulated.

  As described above, the intermediate frequency signal IF and the second local oscillation frequency signal have the same frequency, and the second local oscillation frequency signal is obtained by multiplying the reference frequency f0 of the oscillation circuit 30. Further, the transmission carrier frequency f1, that is, the first local oscillation frequency signal is also generated using the reference frequency f0 of the oscillation circuit 30 as a reference frequency. As described above, by sharing the reference oscillator 31 of the oscillation circuit 30 with various frequency signals necessary for ASK transmission / reception and QPSK transmission / reception, the number of oscillation circuits of the wireless communication device is reduced.

  The internal configuration of the quadrature demodulator 65 is shown in FIG. As shown in FIG. 4, the input intermediate frequency signal IF is distributed by the distributor 651 and supplied to the mixer 652 and the mixer 653. The input second local oscillation frequency signal is directly supplied to the mixer 652 and is supplied to the mixer 653 via the 90 ° phase shift circuit 654.

  The mixer output from the quadrature demodulator 65 is filtered by the LPFs 67 and 68 and output as reception in-phase data Irx and reception quadrature data Qrx.

  When the received carrier wave is QPSK modulated, the received in-phase data Irx and the received quadrature data Qrx are QPSK received data in a π / 4 shift format.

  When the received carrier wave is ASK modulated, the received in-phase data Irx and / or the received quadrature data Qrx are subjected to processing such as amplitude detection in the amplitude demodulation circuit 70 to become ASK received data Arx.

  In this example, the reference frequency f0 of the oscillation circuit 30 is doubled as the second local frequency signal. However, depending on the frequency relationship between the transmission / reception carrier frequencies f1 and f2 and the reference frequency f0, the multiplier 66 is unnecessary. It is also possible to use a frequency that is an integer multiple or a fraction of an integer.

  The automatic gain control circuit 69 controls the gain of the variable gain amplifier 64 by generating a gain control signal based on the received in-phase data Irx and the received quadrature data Qrx so that their amplitudes become a predetermined magnitude.

  The transmission and reception operations of the wireless communication apparatus of the present invention configured as described above will be described in order.

  Whether the wireless communication device performs communication using the ASK modulation method or the QPSK modulation method depends on the modulation method of a communication partner, for example, a wireless communication device installed on the roadside. Whether the communication partner's modulation method is the ASK modulation method or the QPSK modulation method is determined by whether the reception / demodulation circuit 60 can obtain QPSK reception data or ASK reception data. In addition, when a modulation method is determined in advance according to a region or place, the modulation method is used.

  When transmitting by the QPSK modulation method, the transmission / reception switching signal Tx / Rx is at the H level, and the modulation method switching signal QPSK / ASK is at the H level. Thereby, the 1st-4th change-over switch 41, 42, 51, 52 is switched to the one switch terminal a side as shown in FIG.

  In the QPSK modulation circuit 20, the transmission in-phase data Itx and the transmission quadrature data Qtx are input to the quadrature modulator 21. The quadrature modulator 21 performs π / 4 shift QPSK modulation on the transmission carrier according to the transmission in-phase data Itx and the transmission quadrature data Qtx. The QPSK-modulated output from the QPSK modulation circuit 20 is input to the ASK modulation circuit 10. In this case, since the ASK transmission data Atx is at the H level, the driver circuit 13 sets the ASK modulator 11 to the gain “maximum”. Therefore, the ASK modulation circuit 10 functions as an amplifier circuit that amplifies the QPSK modulated wave that is QPSK modulated by the ASK modulator 11 and the AMP 15. Therefore, the QPSK modulated wave subjected to π / 4 shift QPSK modulation is amplified and transmitted from the antenna 1 at the transmission carrier frequency f1.

  When receiving from the communication partner by the QPSK modulation method, since the transmission / reception switching signal Tx / Rx becomes L level, the third and fourth switching switches 51 and 52 of the transmission / reception switching circuit 50 are switched to the other switching terminal b. . In this case, the first and second changeover switches 41 and 42 of the modulation system changeover circuit 40 are also switched to the other changeover terminal b. At the same time, the operation of the QPSK modulation circuit 20 is stopped.

  A QPSK-modulated wave having a frequency f2 modulated by QPSK from the communication partner and a first local oscillation frequency signal having a frequency f1 from the oscillation circuit 30 via the first to third changeover switches 41, 42, 51 (that is, a transmission carrier wave) Are mixed by the mixer 62, and an intermediate frequency signal IF having a frequency f1-f2 (= 40 MHz) is obtained. This intermediate frequency signal IF and the second local oscillation frequency signal obtained by multiplying the reference frequency f 0 from the oscillation circuit 30 by two are input to the quadrature demodulator 65. As a result, the intermediate frequency signal IF is quadrature demodulated, and π / 4 shift format QPSK reception in-phase data Irx and reception quadrature data Qrx are output. In this way, wireless communication by QPSK modulation is performed.

  Next, when transmitting by the ASK modulation method, the transmission / reception switching signal Tx / Rx is at the H level, and the modulation method switching signal QPSK / ASK is at the L level. Thus, the first and second changeover switches 41 and 42 are switched to the other changeover terminal b side, and the third and fourth changeover switches 51 and 52 are switched to one of the changeover terminals a as shown in FIG. Has been switched to the side.

  As a result, the QPSK modulation circuit 20 is disconnected and bypassed by the modulation system switching circuit 40. At the same time, the operation of the QPSK modulation circuit 20 is stopped. Further, the transmission in-phase data Itx and the transmission quadrature data Qtx are not input to the QPSK modulation circuit 20.

  The ASK modulation circuit 10 receives ASK transmission data Atx and a transmission carrier wave from the oscillation circuit 30 through the modulation system switching circuit 40. In the ASK modulator 11 in the ASK modulation circuit 10, the transmission carrier is ASK modulated by the driver circuit 13 in accordance with the ASK transmission data Atx. Therefore, the ASK modulated ASK modulated wave is amplified and transmitted from the antenna 1 at the transmission carrier frequency f1.

  When receiving from the communication partner by the ASK modulation method, the transmission / reception switching signal Tx / Rx is also at the L level together with the modulation method switching signal QPSK / ASK, so that the first to fourth changeover switches 41, 42, 51, 52 are all The other switching terminal b is switched. The operation of the QPSK modulation circuit 20 remains stopped.

  An ASK modulated wave having an ASK-modulated frequency f2 from a communication partner and a first local oscillation frequency signal having a frequency f1 from the oscillation circuit 30 via the first to third changeover switches 41, 42, 51 (that is, a transmission carrier wave) Are mixed by the mixer 62, and an intermediate frequency signal IF having a frequency f1-f2 (= 40 MHz) is obtained. The intermediate frequency signal IF and the second local oscillation frequency signal obtained by multiplying the reference frequency f0 from the oscillation circuit 30 by two are input to the quadrature demodulator 65, and the intermediate frequency signal IF is quadrature demodulated.

  The operation so far is the same as the reception operation of the reception carrier wave that is QPSK modulated. However, in this case, since the received carrier wave is ASK modulated, QPSK received data cannot be obtained from the received in-phase data Irx and the received quadrature data Qrx from the quadrature demodulator 65. However, the amplitude of the reception in-phase data Irx and the reception quadrature data Qrx varies according to the ASK modulation data due to ASK modulation. The amplitude fluctuation is subjected to amplitude detection by the amplitude demodulation circuit 70 to obtain ASK reception data Arx. In this way, wireless communication by ASK modulation is performed.

The figure which shows the whole structure of the radio | wireless communication apparatus of this invention The figure which shows the internal structural example of the oscillation circuit of FIG. The figure which shows the structural example of the orthogonal modulator for performing the QPSK modulation of FIG. The figure which shows the structural example of the orthogonal demodulator for performing the QPSK demodulation of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ASK modulation circuit 11 ASK modulator 12 Variable attenuator 13 Driver circuit 14 LPF
20 QPSK modulation circuit 21 Quadrature modulator 22 AMP
23, 24 LPF
30 Oscillator 31 Reference oscillator 32 Voltage controlled oscillator 33 Phase comparator 34 Loop filter 40 Modulation system switching circuit 41, 42 First and second switch 43 Logic circuit (AND circuit)
44 AMP
50 Transmission / reception switching circuits 51, 52 Third and fourth switching switches 60 Reception / demodulation circuit 61 Low noise amplifier 62 Mixer 63 BPF
64 Variable gain amplifier 65 Quadrature demodulator 66 Multiplier 67, 68 LPF
69 Automatic gain control circuit 70 Amplitude demodulation circuit Atx ASK transmission data Itx transmission in-phase data Qtx transmission quadrature data Arx ASK reception data Irx reception in-phase data Qrx reception quadrature data Tx / Rx transmission / reception switching signal QPSK / ASK modulation system switching signal f0 reference frequency f1 Transmission carrier frequency f2 Reception carrier frequency

Claims (7)

An ASK modulation circuit for ASK modulating a transmission carrier wave using amplitude modulation data;
A PSK modulation circuit that PSK modulates a transmission carrier wave using phase modulation data;
An oscillation circuit that generates at least a transmission carrier; and
A modulation system switching circuit that receives the transmission carrier from the oscillation circuit and switches between connecting the ASK modulation circuit and the PSK modulation circuit in series or bypassing the PSK modulation circuit according to a modulation system switching signal; Have
In the case of ASK modulation, the PSK modulation circuit is bypassed by the modulation system switching circuit, the transmission carrier wave that has passed through the modulation system switching circuit is ASK modulated by the ASK modulation circuit, and transmitted as an ASK modulated wave,
When performing PSK modulation, the transmission carrier is PSK modulated by the PSK modulation circuit, and the PSK modulated PSK modulated wave is transmitted through the ASK modulation circuit without ASK modulation. Wireless communication device. An ASK modulation circuit for ASK modulating a transmission carrier wave using amplitude modulation data;
A PSK modulation circuit that PSK modulates a transmission carrier wave using phase modulation data;
A reception / demodulation circuit for both ASK and PSK, which receives a modulated wave subjected to ASK modulation or PSK modulation and demodulates received data;
An oscillation circuit for generating a reference carrier frequency generated by a reference oscillator and a transmission carrier having a frequency higher than the reference frequency based on the reference frequency;
A modulation scheme switching circuit that receives the transmission carrier from the oscillation circuit and switches between supplying the transmission carrier to the PSK modulation circuit or bypassing the PSK modulation circuit according to a transmission / reception switching signal and a modulation scheme switching signal; ,
In accordance with a transmission / reception switching signal, the transmission carrier wave or PSK modulated wave from the modulation system switching circuit is switched to supply to the ASK modulation circuit or to the reception / demodulation circuit as a first local oscillation frequency signal, and A transmission / reception switching circuit for switching whether to transmit an ASK or PSK modulated wave from the ASK modulation circuit to the outside or to receive a reception signal from the outside,
At the time of transmission, when the transmission / reception switching circuit is switched to the transmission side and ASK modulation is performed, the PSK modulation circuit is bypassed by the modulation system switching circuit, and the transmission carrier wave that has passed through the modulation system switching circuit is transmitted to the ASK modulation circuit. In the case of ASK modulation and transmission as an ASK modulated wave, and in the case of PSK modulation, the transmission carrier is PSK modulated by the PSK modulation circuit, and the PSK modulated PSK modulated wave is not ASK modulated. Transmit through the ASK modulation circuit,
At the time of reception, the transmission / reception switching circuit is switched to the reception side, and the reception / demodulation circuit mixes the reception signal and the first local oscillation frequency signal to mix the reference frequency or an integral multiple thereof or one integral fraction thereof. The intermediate frequency signal is obtained, and the intermediate frequency signal is demodulated using the second local oscillation frequency signal having the same frequency as the intermediate frequency signal to obtain ASK reception data or PSK reception data. Wireless communication device. The modulation system switching circuit is
A first changeover switch having a common terminal connected to the transmission carrier output side of the oscillation circuit and one switching terminal connected to the carrier input side of the PSK modulation circuit;
One switching terminal is connected to the output side of the PSK modulation circuit, the other switching terminal is connected to the other switching terminal of the first switching switch, and a second switching switch for outputting a carrier wave from the common terminal is provided. The wireless communication device according to claim 1, wherein the wireless communication device is characterized.   4. The wireless communication device according to claim 1, wherein the PSK modulator is turned off when it is bypassed by the modulation method switching circuit.   2. The PSK modulator includes a quadrature modulator, wherein the quadrature modulator QPSK modulates a transmission carrier with π / 4 shift QPSK transmission data including transmission in-phase data and transmission quadrature data. The wireless communication device according to any one of 4 to 4.   The oscillation circuit generates a transmission carrier by a phased lock loop circuit based on the reference frequency, and the reference frequency is equal to or equal to a difference frequency between the transmission carrier frequency and the reception carrier frequency. The wireless communication device according to claim 2, wherein the wireless communication device is an integer multiple of 1 or a fraction of an integer. The reception / demodulation circuit includes a quadrature demodulator, and the quadrature demodulator is a second local oscillation frequency formed on the basis of the reference frequency signal so as to have the same frequency as the intermediate frequency signal and the intermediate frequency signal. 7. The radio communication apparatus according to claim 2, wherein quadrature demodulation is performed using a signal to obtain reception in-phase data and reception quadrature data or ASK reception data of π / 4 shift QPSK.