CN106533460A - Wireless transmitter and control method thereof - Google Patents

Abstract

The present invention provides a wireless transmitter and a control method thereof. The wireless transmitter includes a phase-locked module and a power amplifier; The frequency-converted baseband signal output by the phase-locking module is amplified. Compared with the prior art, the present invention provides a wireless transmitter and its control method, which uses a phase-locked module to convert the frequency of the baseband signal, which saves devices such as multipliers and adders in the prior art, and simplifies the transmitter structure and reduce hardware costs.

Description

A wireless transmitter and its control method

technical field

The invention relates to the technical field of micro-power wireless communication, in particular to a wireless transmitter and a control method thereof.

Background technique

Micropower wireless communication is a communication technology widely used in the field of industrial data acquisition, which has the advantages of strong diffraction ability and long recognition distance. At present, the wireless transmitter used for micro-power wireless communication is mainly a direct conversion transmitter. Figure 1 is a schematic structural diagram of a direct conversion transmitter. As shown in the figure, the transmitter includes two multipliers and an adder. The direct conversion transmitter mainly uses a combination of multipliers, adders and filters to directly up-convert baseband data, but this circuit structure not only increases the hardware cost and design complexity of the transmitter, but also reduces its reliability. sex.

Contents of the invention

In order to overcome the defects of the prior art, the present invention provides a wireless transmitter and its control method.

In the first aspect, the technical scheme of a kind of wireless transmitter among the present invention is:

The wireless transmitter includes a phase-locked module and a power amplifier;

The phase-locked module is used to up-convert the baseband signal according to the local oscillation signal;

The power amplifier is used to amplify the frequency-converted baseband signal output by the phase-locked module.

Further, a preferred technical solution provided by the present invention is: the phase-locked module includes a modulator and a phase-locked loop; the modulator, the phase-locked loop and the power amplifier are connected in sequence.

Further, a preferred technical solution provided by the present invention is:

The modulator is a high order Sigma Delta modulator.

Further, a preferred technical solution provided by the present invention is: the phase-locked loop includes a phase detector, a loop filter, a voltage-controlled oscillator and a frequency divider connected in sequence;

One input end of the phase detector is connected to the local oscillator and receives the local oscillation signal output by it, and the other input end is connected to the output end of the frequency divider;

The other input terminal of the frequency divider is connected to the modulator;

The other output end of the voltage controlled oscillator is connected with the power amplifier.

Further, a preferred technical solution provided by the present invention is:

The wireless transmitter also includes a filter;

The input end of the filter is connected with the information source and receives the baseband signal sent by it, and the output end is connected with the phase locking module.

Further, a preferred technical solution provided by the present invention is:

The filter is a Gaussian filter.

Further, a preferred technical solution provided by the present invention is:

The wireless transmitter also includes an antenna module connected to the output end of the power amplifier.

Further, a preferred technical solution provided by the present invention is:

The frequency of the baseband signal after frequency conversion is 470MHz-510MHz.

In the second aspect, the technical solution of a control method of a wireless transmitter in the present invention is:

The control method includes: adjusting the frequency division ratio of the frequency divider in the phase-locked module to change the frequency of the baseband signal.

Further, a preferred technical solution provided by the present invention is:

The frequency division ratio of the adjusted frequency divider is shown in the following formula (1):

N ₂ =N ₁ (1+γ) (1)

Among them, γ is the adjustment coefficient, -1<γ<1 and γ≠0; N ₁ and N ₂ are the frequency division ratios of the frequency divider before adjustment and after adjustment, respectively.

Further, a preferred technical solution provided by the present invention is:

The frequency division ratio adjustment range of the frequency divider is (N ₁ -N _o )～(N ₁ +N _o );

Among them, N ₁ is the frequency division ratio of the frequency divider before adjustment, and N _o is the order number of the modulator in the phase-locked module.

Compared with the closest prior art, the beneficial effects of the present invention are:

1. A wireless transmitter provided by the present invention uses a phase-locked module to convert the frequency of the baseband signal, which saves devices such as multipliers and adders in the prior art, simplifies the transmitter structure and reduces hardware costs;

2. The wireless transmitter control method provided by the present invention can change the frequency of the baseband signal by adjusting the frequency division ratio of the frequency divider in the phase-locked module, and the operation is simple.

Description of drawings

Figure 1: Schematic diagram of the structure of a direct conversion frequency transmitter;

Fig. 2: A schematic structural diagram of a wireless transmitter in an embodiment of the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

A wireless transmitter provided by an embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a schematic structural diagram of a wireless transmitter in an embodiment of the present invention. As shown in the figure, the wireless transmitter in this embodiment includes a phase-locked module and a power amplifier. in,

The phase-locking module is used for up-converting the baseband signal according to the local oscillation signal.

The power amplifier is used to amplify the frequency-converted baseband signal output by the phase-locking module.

In this embodiment, a phase-locked module is used to convert the frequency of the baseband signal, which saves devices such as a multiplier and an adder in the prior art, simplifies the structure of the transmitter, and reduces hardware costs.

Further, the phase locking module in this embodiment may include the following structures.

The phase-locked module in this embodiment includes a modulator and a phase-locked loop, and the modulator, the phase-locked loop and the power amplifier are connected in sequence. in,

1. Modulator

In this embodiment, the modulator can provide the enable signal for selecting the frequency division ratio to the phase-locked loop, that is, its output signal is a time-varying signal, and the phase-locked loop can output the frequency division corresponding to the time-varying signal according to the time-varying signal. Compare. Wherein, the modulator may adopt a high-order Sigma Delta modulator.

2. PLL

As shown in the figure, the phase-locked loop includes a phase detector, a loop filter, a voltage-controlled oscillator and a frequency divider connected in sequence. One input end of the phase detector is connected with the local oscillator and receives the output local oscillation signal, and the other input end is connected with the output end of the frequency divider. in,

The other input terminal of the frequency divider is connected with the modulator to receive the enable signal of the frequency division ratio output by the modulator.

The other output terminal of the voltage-controlled oscillator is connected to the power amplifier, and the baseband signal after frequency conversion is sent to the power amplifier for amplification.

Further, the wireless transmitter in this embodiment may also include the following structure.

The wireless transmitter in this embodiment also includes a filter and an antenna module. in,

1. Filter

In this embodiment, the input end of the filter is connected to the information source and receives the baseband signal sent by it, and the output end is connected to the phase locking module. In this embodiment, the filter can be a Gaussian filter, which filters the baseband signal so that the pulse envelope of the baseband signal has neither a steep edge nor an inflection point, so the spectral characteristics of the baseband signal are better, and the required bandwidth is relatively small. Narrow, improving bandwidth utilization.

2. Antenna module

In this embodiment, the antenna module is connected to the output end of the power amplifier, and the baseband signal amplified by the power amplifier can be transmitted to each receiving device through the wireless communication network. Wherein, the frequency of the baseband signal output by the wireless transmitter is 470MHz-510MHz.

The invention also provides a control method of the wireless transmitter, and provides specific embodiments.

In this embodiment, the frequency ω _d of the baseband signal is much lower than the frequency ω _c of the local oscillator signal, and the frequency of the baseband signal is up-converted, that is, the frequency ω _d is increased to ω _d +ω _c . Among them, ω _d + ω _c can be expressed as

In this embodiment, the frequency of the baseband signal is changed by adjusting the frequency division ratio of the frequency divider in the phase-locked module, and the adjusted frequency divider frequency division ratio is shown in the following formula (1):

N ₂ =N ₁ (1+γ) (1)

Among them, γ is the adjustment coefficient, -1<γ<1 and γ≠0; N ₁ and N ₂ are the frequency division ratios of the frequency divider before adjustment and after adjustment, respectively. The frequency division ratio adjustment range of the frequency divider is (N ₁ -N _o )˜(N ₁ +N _o ), where N _o is the order number of the modulator in the phase-locked module.

Assuming that the frequency of the local oscillation signal before and after the adjustment of the frequency divider of the phase-locking module is F _b and F _out respectively, then the output signal of the frequency divider after adjustment according to formula (1), that is, the frequency of the local oscillation signal is as follows (2 ) as shown:

F _out ＝F _b ×N ₁ (1+γ) (2)

As previously known:

ω _c =F _b ×N ₁ (3)

Substitute formula (3) into formula (2) to get:

F _out ＝ω _c +F _b ×N ₁ ×γ (4)

The adjustment coefficient γ is a variable, so in this embodiment it can be set as:

Substitute formula (5) into formula (4) to get:

F _out ＝ω _c +ω _d (6)

Through the above process, it can be determined that the frequency of the baseband signal can be changed after the frequency division ratio of the frequency divider in the phase-locked module is adjusted, that is, the frequency can be up-converted.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (11)

1. A wireless transmitter, characterized in that, the wireless transmitter includes a phase-locked module and a power amplifier; The phase-locked module is used to up-convert the baseband signal according to the local oscillation signal; The power amplifier is used to amplify the frequency-converted baseband signal output by the phase-locked module. 2. A kind of wireless transmitter as claimed in claim 1, is characterized in that, described phase-locked module comprises modulator and phase-locked loop; Described modulator, phase-locked loop and power amplifier are connected in sequence. 3. A kind of wireless transmitter as claimed in claim 2, is characterized in that, The modulator is a high order Sigma Delta modulator. 4. A kind of wireless transmitter as claimed in claim 2, is characterized in that, described phase-locked loop comprises phase detector, loop filter, voltage controlled oscillator and frequency divider connected in sequence; One input end of the phase detector is connected to the local oscillator and receives the local oscillation signal output by it, and the other input end is connected to the output end of the frequency divider; The other input terminal of the frequency divider is connected to the modulator; The other output end of the voltage controlled oscillator is connected with the power amplifier. 5. A kind of wireless transmitter as claimed in claim 1, is characterized in that, The wireless transmitter also includes a filter; The input end of the filter is connected with the information source and receives the baseband signal sent by it, and the output end is connected with the phase locking module. 6. A kind of wireless transmitter as claimed in claim 1, is characterized in that, The filter is a Gaussian filter. 7. A kind of wireless transmitter as claimed in claim 1, is characterized in that, The wireless transmitter also includes an antenna module connected to the output end of the power amplifier. 8. A kind of wireless transmitter as claimed in claim 1, is characterized in that, The frequency of the baseband signal after frequency conversion is 470MHz-510MHz. 9. A method for controlling a wireless transmitter according to any one of claims 1-8, wherein: The control method includes: adjusting the frequency division ratio of the frequency divider in the phase-locked module to change the frequency of the baseband signal. 10. The control method of a kind of wireless transmitter as claimed in claim 9, is characterized in that, The frequency division ratio of the adjusted frequency divider is shown in the following formula (1): N ₂ =N ₁ (1+γ) (1) Among them, γ is the adjustment coefficient, -1<γ<1 and γ≠0; N ₁ and N ₂ are the frequency division ratios of the frequency divider before adjustment and after adjustment, respectively. 11. The control method of a kind of wireless transmitter as claimed in claim 9, is characterized in that, The frequency division ratio adjustment range of the frequency divider is (N ₁ -N _o )～(N ₁ +N _o ); Among them, N ₁ is the frequency division ratio of the frequency divider before adjustment, and N _o is the order number of the modulator in the phase-locked module.