阅读说明：本技术 一种用于民航设备中的多普勒全向信标装置 (Doppler omnidirectional beacon device used in civil aviation equipment ) 是由 张锡忠 高津 赵晶晶 王新芳 张媛媛 王志军 于 2019-11-29 设计创作，主要内容包括：本发明涉及一种用于民航设备中的多普勒全向信标装置,包括信号激励单元、调幅单元、边带振荡单元、边带信号功放电路和基准信号功放电路,信号激励单元的输入端与监控天线连接,信号激励单元的输出端与调幅模块的输入端连接,边带信号功放电路和基准信号功放电路并联设置,边带信号功放电路的输入端通过边带振荡单元与调幅单元的输出端连接,基准信号功放电路的输入端分别与调幅单元的输出端连接,边带信号功放电路的输出端与边带天线连接,基准信号功放电路的输出端与基准天线连接。本发明能够产生精确的边带信号、基准信号,提高民航设备的安全性。(The invention relates to a Doppler omnidirectional beacon device used in civil aviation equipment, which comprises a signal excitation unit, an amplitude modulation unit, a sideband oscillation unit, a sideband signal power amplification circuit and a reference signal power amplification circuit, wherein the input end of the signal excitation unit is connected with a monitoring antenna, the output end of the signal excitation unit is connected with the input end of an amplitude modulation module, the sideband signal power amplification circuit and the reference signal power amplification circuit are arranged in parallel, the input end of the sideband signal power amplification circuit is connected with the output end of the amplitude modulation unit through the sideband oscillation unit, the input end of the reference signal power amplification circuit is respectively connected with the output end of the amplitude modulation unit, the output end of the sideband signal power amplification circuit is connected with the sideband antenna, and the output end of the reference signal power amplification circuit is connected with. The invention can generate accurate sideband signals and reference signals and improve the safety of civil aviation equipment.)

1. A doppler omni-directional beacon apparatus for use in civil aviation equipment, characterized by: the monitoring device comprises a signal excitation unit, an amplitude modulation unit, a sideband oscillation unit, a sideband signal power amplification circuit and a reference signal power amplification circuit, wherein the input end of the signal excitation unit is connected with a monitoring antenna, the output end of the signal excitation unit is connected with the input end of an amplitude modulation module, the sideband signal power amplification circuit and the reference signal power amplification circuit are arranged in parallel, the input end of the sideband signal power amplification circuit is connected with the output end of the amplitude modulation unit through the sideband oscillation unit, the input end of the reference signal power amplification circuit is respectively connected with the output end of the amplitude modulation unit, the output end of the sideband signal power amplification circuit is connected with a sideband antenna, and the output end of the reference signal power amplification circuit is connected with a reference;

the signal excitation unit comprises a signal processing circuit, a digital-to-analog conversion circuit, a band-pass filter circuit, a frequency synthesizer circuit and a clock circuit, wherein the input end of the signal processing circuit is connected with the monitoring antenna, the output end of the signal processing circuit, the digital-to-analog conversion circuit, the band-pass filter circuit and the frequency synthesizer circuit are sequentially connected, and the clock circuit is respectively connected with the output ends of the signal processing circuit and the digital-to-analog conversion circuit;

the amplitude modulation unit comprises a first amplitude modulation circuit and a second amplitude modulation circuit which are arranged in parallel, the input ends of the first amplitude modulation circuit and the second amplitude modulation circuit are respectively connected with the output end of the frequency synthesizer circuit, the output end of the first amplitude modulation circuit is respectively connected with the sideband oscillation unit, and the output end of the second amplitude modulation circuit is connected with the reference signal power amplifier circuit;

the sideband oscillation unit comprises an upper sideband oscillator and a lower sideband oscillator which are arranged in parallel, the sideband signal power amplifier circuit comprises an upper sideband signal power amplifier circuit and a lower sideband signal power amplifier circuit, the upper sideband signal power amplifier circuit is connected with the upper sideband oscillator, and the lower sideband signal power amplifier circuit is connected with the lower sideband oscillator.

2. The Doppler omnidirectional beacon device used in civil aviation equipment according to claim 1, wherein: the signal excitation unit still includes power supply converting circuit, power supply converting circuit is in order to right the band-pass filter circuit power supply, power supply converting circuit includes DC/DC converting circuit, LDO filter circuit, DC/DC converting circuit's input is connected with external power supply, DC/DC converting circuit's output and LDO filter circuit are connected, LDO filter circuit further is connected with band-pass filter circuit.

3. The Doppler omnidirectional beacon device used in civil aviation equipment according to claim 1, wherein: the digital-to-analog conversion circuit comprises a DAC0830LCM interface circuit and a first operational amplifier, wherein the input end of the DAC0830LCM interface circuit is connected with the signal processing circuit, the first current output end of the DAC0830LCM interface circuit is connected with the inverting end of the first operational amplifier, the second current output end of the DAC0830LCM interface circuit is connected with the non-inverting end of the first operational amplifier, and the output end of the first operational amplifier is connected with the input end of the band-pass filter circuit.

4. The Doppler omnidirectional beacon device used in civil aviation equipment according to claim 1, wherein: the band-pass filter circuit comprises a second resistor, a third resistor, a feedback resistor, a second operational amplifier, a third capacitor and a fourth capacitor, wherein one end of the second resistor, the non-inverting end of the second operational amplifier and one end of the third resistor are respectively connected with the output end of the digital-to-analog conversion circuit, the other end of the second resistor is respectively connected with the other end of the third resistor, one end of the third capacitor and one end of the fourth capacitor, the other end of the third capacitor is respectively connected with the inverting end of the second operational amplifier and one end of the feedback resistor, and the output end of the second operational amplifier and the other end of the feedback resistor are respectively connected with the amplitude modulation circuit.

5. The Doppler omnidirectional beacon device used in civil aviation equipment according to claim 1, wherein: the first amplitude modulation circuit and the second amplitude modulation circuit both comprise first inductors, one ends of the first inductors are connected with the output end of the band-pass filter circuit and one ends of the first capacitors, the other ends of the first capacitors are grounded, the other ends of the first inductors are connected with one ends of the second capacitors and the negative electrodes of the Schottky diodes, the other ends of the second capacitors are grounded, the positive electrodes of the Schottky diodes are connected with one ends of the first resistors, and the other ends of the first resistors are grounded.

6. The Doppler omnidirectional beacon device used in civil aviation equipment according to claim 1, wherein: the upper sideband signal power amplifier circuit, the lower sideband signal power amplifier circuit and the reference signal power amplifier circuit respectively comprise a first transmitting tube, a second transmitting tube, a fourth resistor and a fifth resistor, the base electrode of the first transmitting tube is connected with the base electrode of the second transmitting tube, the fourth resistor is connected between the collector electrode and the emitter electrode of the first transmitting tube, the collector electrode of the first transmitting tube is also connected with the first input end of the impedance transformation circuit, and the emitter electrode of the first transmitting tube and the collector electrode of the second transmitting tube are grounded; and a fifth resistor is connected between the collector and the emitter of the second emission tube.

7. The Doppler omnidirectional beacon device used in civil aviation equipment according to claim 1, wherein: the signal processing circuit adopts an FPGA chip with the model of EPC 1441.

8. The Doppler omnidirectional beacon device used in civil aviation equipment as claimed in claim 7, wherein: the frequency synthesizer circuit comprises a DDS chip, and the DDS chip is connected with the output end of the FPGA chip.

Technical Field

The invention relates to the technical field of electric power, in particular to a Doppler omnidirectional beacon device used in civil aviation equipment.

Background

The omnidirectional beacon device is mainly applied to short-distance and medium-distance guiding work of an airplane at present as radio navigation equipment recommended by the international civil aviation organization. The stable and orderly operation of the radio navigation equipment can provide effective safety guarantee for short-range navigation in the airplane, and in addition, the normal and stable operation of scientific research and test flight can be ensured. However, in the conventional method for generating the reference signal and the sideband signal by the omnidirectional beacon device, the reference generator generates the reference signal first, and then the sideband signal is generated according to the reference signal, and in such a signal generation method, if an error occurs during the generation of the reference signal, the subsequently generated sideband signal also has an error, so that the signal error generated by the omnidirectional beacon device is large, the accuracy is low, and the safety performance of civil aviation equipment cannot be guaranteed.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a Doppler omnidirectional beacon device for civil aviation equipment, which can generate accurate sideband signals and reference signals and improve the safety of the civil aviation equipment.

The invention relates to a Doppler omnidirectional beacon device used in civil aviation equipment, which comprises a signal excitation unit, an amplitude modulation unit, a sideband oscillation unit, a sideband signal power amplification circuit and a reference signal power amplification circuit, wherein the input end of the signal excitation unit is connected with a monitoring antenna, the output end of the signal excitation unit is connected with the input end of an amplitude modulation module, the sideband signal power amplification circuit and the reference signal power amplification circuit are arranged in parallel, the input end of the sideband signal power amplification circuit is connected with the output end of the amplitude modulation unit through the sideband oscillation unit, the input end of the reference signal power amplification circuit is respectively connected with the output end of the amplitude modulation unit, the output end of the sideband signal power amplification circuit is connected with the sideband antenna, and the output end of the reference signal power amplification circuit is connected with the reference antenna;

the signal excitation unit comprises a signal processing circuit, a digital-to-analog conversion circuit, a band-pass filter circuit, a frequency synthesizer circuit and a clock circuit, wherein the input end of the signal processing circuit is connected with the monitoring antenna, the output end of the signal processing circuit, the digital-to-analog conversion circuit, the band-pass filter circuit and the frequency synthesizer circuit are sequentially connected, and the clock circuit is respectively connected with the output ends of the signal processing circuit and the digital-to-analog conversion circuit;

the amplitude modulation unit comprises a first amplitude modulation circuit and a second amplitude modulation circuit which are arranged in parallel, the input ends of the first amplitude modulation circuit and the second amplitude modulation circuit are respectively connected with the output end of the frequency synthesizer circuit, the output end of the first amplitude modulation circuit is respectively connected with the sideband oscillation unit, and the output end of the second amplitude modulation circuit is connected with the reference signal power amplifier circuit;

the sideband oscillation unit comprises an upper sideband oscillator and a lower sideband oscillator which are arranged in parallel, the sideband signal power amplifier circuit comprises an upper sideband signal power amplifier circuit and a lower sideband signal power amplifier circuit, the upper sideband signal power amplifier circuit is connected with the upper sideband oscillator, and the lower sideband signal power amplifier circuit is connected with the lower sideband oscillator.

Preferably, the signal excitation unit further includes a power conversion circuit, the power conversion circuit is to the power supply of the band-pass filter circuit, the power conversion circuit includes a DC/DC conversion circuit and an LDO filter circuit, the input end of the DC/DC conversion circuit is connected with an external power supply, the output end of the DC/DC conversion circuit is connected with the LDO filter circuit, and the LDO filter circuit is further connected with the band-pass filter circuit.

Preferably, in any of the above schemes, the digital-to-analog conversion circuit includes a DAC0830LCM interface circuit and a first operational amplifier, an input terminal of the DAC0830LCM interface circuit is connected to the signal processing circuit, a first current output terminal of the DAC0830LCM interface circuit is connected to an inverting terminal of the first operational amplifier, a second current output terminal of the DAC0830LCM interface circuit is connected to a non-inverting terminal of the first operational amplifier, and an output terminal of the first operational amplifier is connected to an input terminal of the band-pass filter circuit.

Preferably, in any of the above schemes, the band-pass filter circuit includes a second resistor, a third resistor, a feedback resistor, a second operational amplifier, a third capacitor, and a fourth capacitor, one end of the second resistor, one end of the second operational amplifier and one end of the third resistor are respectively connected to the output terminal of the digital-to-analog converter circuit, the other end of the second resistor is respectively connected to the other end of the third resistor, one end of the third capacitor and one end of the fourth capacitor, the other end of the third capacitor is respectively connected to the inverting terminal of the second operational amplifier and one end of the feedback resistor, and the output terminal of the second operational amplifier and the other end of the feedback resistor are respectively connected to the amplitude modulation circuit.

Preferably, in any of the above schemes, the first amplitude modulation circuit and the second amplitude modulation circuit each include a first inductor, one end of the first inductor is connected to the output end of the band-pass filter circuit and one end of the first capacitor, the other end of the first capacitor is grounded, the other end of the first inductor is connected to one end of the second capacitor and the negative electrode of the schottky diode, the other end of the second capacitor is grounded, the positive electrode of the schottky diode is connected to one end of the first resistor, and the other end of the first resistor is grounded.

Preferably, in any of the above schemes, the upper sideband signal power amplifier circuit, the lower sideband signal power amplifier circuit and the reference signal power amplifier circuit each include a first transmitting tube, a second transmitting tube, a fourth resistor and a fifth resistor, a base of the first transmitting tube is connected with a base of the second transmitting tube, the fourth resistor is connected between a collector and an emitter of the first transmitting tube, the collector of the first transmitting tube is further connected with a first input end of the impedance transformation circuit, and the emitter of the first transmitting tube and the collector of the second transmitting tube are all grounded; and a fifth resistor is connected between the collector and the emitter of the second emission tube.

In any of the above solutions, preferably, the signal processing circuit uses an FPGA chip with model EPC 1441.

In any of the above schemes, preferably, the frequency synthesizer circuit includes a DDS chip, and the DDS chip is connected to an output terminal of the FPGA chip.

Compared with the prior art, the invention has the advantages and beneficial effects that:

1. the reference signal and the sideband signal are generated in parallel and are mutually independent, so that relative influence between the signals is prevented, signal errors are reduced, the signal transmission accuracy is improved, stable and orderly operation of civil aviation equipment is guaranteed, and the safety performance is guaranteed. Through being equipped with band-pass filter circuit, can filtering clutter in the transmission signal, through being equipped with the amplitude modulation unit, realize the amplitude modulation to the transmission signal, optimize the signal to the efficiency and the precision of sideband signal and reference signal transmission have been improved.

2. The band-pass filter circuit filters noise waves of signals by adopting a double RC circuit in series connection, and the filter effect is enhanced. The second operational amplifier is connected with the feedback resistor in parallel, so that the limitation of the fixed gain bandwidth can be avoided, the high gain of the loop can be kept while the gain is improved by reducing the resistance value of the feedback resistor, the influence of an input bias signal on the output is reduced, and the error is reduced.

3. The power amplifier circuit can amplify the received 5 paths of signals, and two-stage amplification is carried out through the first transmitting tube and the second transmitting tube so as to meet the power requirement of subsequent antenna distribution unit transmission. In addition, when one of the first transmitting tube and the second transmitting tube breaks down, the other transmitting tube can still amplify the signal, so that the impedance matching transformation of the subsequent impedance transformation circuit on the signal is not influenced, and the stability of the whole circuit is greatly improved. In addition, the impedance conversion circuit is arranged to perform impedance matching on the amplified signal, so that the impedance of the signal is matched with the impedance of the antenna to be transmitted, and the strength of the signal is higher.

The invention further discloses a Doppler omnidirectional beacon device used in civil aviation equipment, which is described in the following with reference to the accompanying drawings.

Drawings

Fig. 1 is a block diagram of a doppler omnidirectional beacon device used in civil aviation equipment according to the present invention;

FIG. 2 is a schematic circuit diagram of a digital-to-analog conversion circuit in a Doppler omnidirectional beacon device for civil aviation equipment according to the present invention;

FIG. 3 is a schematic circuit diagram of a bandpass filter circuit in a Doppler omnidirectional beacon apparatus used in civil aviation equipment according to the present invention;

FIG. 4 is a schematic circuit diagram of first and second amplitude modulation circuits of a Doppler omnidirectional beacon apparatus for civil aviation equipment according to the present invention;

FIG. 5 is a schematic circuit diagram of a power amplifier circuit in a Doppler omnidirectional beacon device used in civil aviation equipment according to the present invention;

FIG. 6 is a schematic circuit diagram of a DDS chip in a Doppler omnidirectional beacon device used in civil aviation equipment according to the present invention;

wherein: 1. a signal processing circuit; 2. a digital-to-analog conversion circuit; 3. a band-pass filter circuit; 4. a frequency synthesizer circuit; 5. a first amplitude modulation circuit; 6. a second amplitude modulation circuit; 7. an upper sideband oscillator; 8. an upper sideband signal power amplifier circuit; 9. a lower sideband oscillator; 10. an upper sideband signal power amplifier circuit; 11. a reference signal power amplifier circuit; 12. a clock circuit.

Detailed Description

As shown in fig. 1, the present invention provides a doppler omnidirectional beacon device for use in civil aviation equipment, which includes a signal excitation unit, an amplitude modulation unit, a sideband oscillation unit, a sideband signal power amplification circuit, and a reference signal power amplification circuit 11, wherein an input end of the signal excitation unit is connected to a monitoring antenna, an output end of the signal excitation unit is connected to an input end of an amplitude modulation module, the sideband signal power amplification circuit and the reference signal power amplification circuit 11 are arranged in parallel, an input end of the sideband signal power amplification circuit is connected to an output end of the amplitude modulation unit through the sideband oscillation unit, an input end of the reference signal power amplification circuit 11 is connected to output ends of the amplitude modulation unit, an output end of the sideband signal power amplification circuit is connected to the sideband antenna, and an output end of the reference signal power amplification circuit 11 is.

In this embodiment, the signal excitation unit receives a signal of the monitoring antenna, and performs conversion processing on the antenna signal to generate a 1-channel reference signal and a 4-channel sideband signal. The amplitude modulation unit performs amplitude modulation on the received original 5 paths of signals to adjust the received original 5 paths of signals into 5 paths of signals with required amplitude. After the 4-way sideband signals after the amplitude modulation are modulated and processed by the sideband oscillation unit, corresponding modulation signals are generated and are amplified by the sideband signal power amplification circuit, 1-way reference signals after the amplitude modulation are amplified by the reference signal power amplification circuit 11, the 4-way sideband signals and the 1-way reference signals are amplified to the transmitted power, the 4-way sideband signals are transmitted and fed by the sideband antenna, and the 1-way reference signals are transmitted and fed by the reference antenna.

Specifically, the signal excitation unit comprises a signal processing circuit 1, a digital-to-analog conversion circuit 2, a band-pass filter circuit 3, a frequency synthesizer circuit 4 and a clock circuit 12, wherein the input end of the signal processing circuit 1 is connected with the monitoring antenna, the output end of the signal processing circuit 1, the digital-to-analog conversion circuit 2, the band-pass filter circuit 3 and the frequency synthesizer circuit 4 are sequentially connected, and the clock circuit 12 is respectively connected with the output ends of the signal processing circuit 1 and the digital-to-analog conversion circuit 2. The amplitude modulation unit comprises a first amplitude modulation circuit 5 and a second amplitude modulation circuit 6 which are arranged in parallel, the input ends of the first amplitude modulation circuit 5 and the second amplitude modulation circuit 6 are respectively connected with the output end of the frequency synthesizer circuit 4, the output end of the first amplitude modulation circuit 5 is respectively connected with the sideband oscillation unit, and the output end of the second amplitude modulation circuit 6 is connected with the reference signal power amplification circuit 11. The sideband oscillation unit comprises an upper sideband oscillator 7 and a lower sideband oscillator 9 which are arranged in parallel, the sideband signal power amplifier circuit comprises an upper sideband signal power amplifier circuit 108 and a lower sideband signal power amplifier circuit, the upper sideband signal power amplifier circuit 108 is connected with the upper sideband oscillator 7, and the lower sideband signal power amplifier circuit is connected with the lower sideband oscillator 9.

The signal processing circuit 1 receives signals of a monitoring antenna, converts the antenna signals to generate digital signals, the digital-to-analog conversion circuit 2 converts the received digital signals to analog signals, clutter in the analog signals is filtered by the band-pass filter circuit 3, and the analog signals after the clutter is filtered are processed by the frequency synthesizer circuit 4 to generate upper sideband signals, lower sideband signals and reference signals. The upper sideband signal and the lower sideband signal are respectively and correspondingly provided with a first amplitude modulation circuit 5, the upper sideband signal and the lower sideband signal are respectively subjected to amplitude clamping through the first amplitude modulation circuit 5 and then are respectively screened through a sideband oscillation unit, so that the upper sideband signal is transmitted to an upper sideband signal power amplification circuit 108 through an upper sideband oscillator 7 for power amplification, the lower sideband signal is transmitted to a lower sideband signal power amplification circuit through a lower sideband oscillator 9 for power amplification, and the amplified upper sideband signal and the amplified lower sideband signal are transmitted through a sideband antenna. The reference signal is provided with a second amplitude modulation circuit 6, the reference signal is subjected to amplitude clamping through the second amplitude modulation circuit 6, power amplification is carried out through a reference signal power amplification circuit 11, and the amplified reference signal is transmitted through a reference antenna. In addition, clock circuit 12 may provide a reference clock.

The reference signal and the sideband signal are generated in parallel and are independent to each other, so that the relative influence between the signals is prevented, the signal error is reduced, the signal transmission accuracy is improved, the stable and ordered operation of civil aviation equipment is ensured, and the safety performance is guaranteed. Through being equipped with band-pass filter circuit 3, can filtering clutter in the transmission signal, through being equipped with the amplitude modulation unit, realize the amplitude modulation to the transmission signal, optimize the signal to the efficiency and the precision of sideband signal and reference signal transmission have been improved.

Furthermore, the signal excitation unit further comprises a power conversion circuit, the power conversion circuit supplies power to the band-pass filter circuit 3, the power conversion circuit comprises a DC/DC conversion circuit and an LDO filter circuit, the input end of the DC/DC conversion circuit is connected with an external power supply, the output end of the DC/DC conversion circuit is connected with the LDO filter circuit, and the LDO filter circuit is further connected with the band-pass filter circuit 3. The voltage provided by the external power supply is converted by the DC/DC conversion circuit, and then the required voltage is output to supply power to the band-pass filter circuit 3.

Further, as shown in fig. 2, the digital-to-analog conversion circuit 2 includes a DAC0830LCM interface circuit and a first operational amplifier AR1, an input terminal of the DAC0830LCM interface circuit is connected to the signal processing circuit 1, a first current output terminal of the DAC0830LCM interface circuit is connected to an inverting terminal of the first operational amplifier AR1, a second current output terminal of the DAC0830LCM interface circuit is connected to a non-inverting terminal of the first operational amplifier AR1, and an output terminal of the first operational amplifier AR1 is connected to an input terminal of the band-pass filter circuit 3.

Further, as shown in fig. 3, the band-pass filter circuit 3 includes a second resistor R2, a third resistor R3, a feedback resistor RF, a second operational amplifier AR2, a third capacitor C3 and a fourth capacitor C4, wherein one end of the second resistor R2, one end of the second operational amplifier and one end of the third resistor R3 are respectively connected to the output end of the digital-to-analog converter circuit 2, the other end of the second resistor R2 is respectively connected to the other end of the third resistor R3, one end of the third capacitor C3 and one end of the fourth capacitor C4, the other end of the third capacitor C3 is respectively connected to the inverting end of the second operational amplifier AR2 and one end of the feedback resistor RF, and the output end of the second operational amplifier AR2 and the other end of the feedback resistor RF are respectively connected to the amplitude modulation circuit. Clutter of signals is filtered out in series by adopting a double RC circuit, and the filtering effect is enhanced. The second operational amplifier AR2 can avoid the limitation of the fixed gain bandwidth by connecting the feedback resistor RF in parallel, and can maintain the loop high gain while increasing the gain by reducing the resistance of the feedback resistor RF, and reduce the influence of the input bias signal on the output to reduce the error.

Further, the first amplitude modulation circuit 5 and the second amplitude modulation circuit 6 each employ a circuit as shown in fig. 4. The first amplitude modulation circuit 5 will be described as an example. The first amplitude modulation circuit 5 comprises a first inductor L1, one end of the first inductor L1 is connected with the output end of the band-pass filter circuit 3 and one end of a first capacitor C1, the other end of the first capacitor C1 is grounded, the other end of the first inductor L1 is connected with one end of a second capacitor C2 and the cathode of a schottky diode D1, the other end of the second capacitor C2 is grounded, the anode of the schottky diode D1 is connected with one end of a first resistor R1, and the other end of the first resistor R1 is grounded. The filter adjustment processing is carried out on the 4-sideband signals transmitted by the band-pass filter through the inductance and capacitance combined LC network, then amplitude clamping is carried out on the sideband signals through the Schottky diode, parameter values of the diode and the resistor R1 are selected according to the required amplitude, and then amplitude modulation of the sideband signals is achieved, so that the sideband signals are adjusted to the required value, subsequent signal amplification processing is facilitated, and the efficiency and the accuracy of sideband signal transmission are improved.

Similarly, the inductor and capacitor combined LC network is used for filtering and adjusting the reference signal of the 1-channel transmitted by the band-pass filter, the Schottky diode is further used for clamping the amplitude of the reference signal, the diode and the resistor R1 are selected according to the required amplitude, and then the amplitude modulation of the reference signal is realized, so that the reference signal is adjusted to the required value, the subsequent signal amplification processing is facilitated, and the emission efficiency and precision of the reference signal are improved.

Further, the upper sideband signal power amplifier circuit 108, the lower sideband signal power amplifier circuit and the reference signal power amplifier circuit 11 are all adopted as shown in fig. 5. The sideband signal power amplifier circuit 108 comprises a first emitter tube Q1, a second emitter tube Q2, a fourth resistor R4 and a fifth resistor R5, wherein the base of the first emitter tube Q1 is connected with the base of the second emitter tube Q2, a fourth resistor R4 is connected between the collector and the emitter of the first emitter tube Q1, the collector of the first emitter tube Q1 is also connected with the first input end of the impedance transformation circuit, and the emitter of the first emitter tube Q1 and the collector of the second emitter tube Q2 are both grounded; a fifth resistor R5 is connected between the collector and the emitter of the second emitter tube Q2.

The power amplifier circuit in the structure can amplify the received 5 paths of signals, and two-stage amplification is carried out through the first transmitting tube Q1 and the second transmitting tube Q2, so that the power requirement of subsequent antenna distribution unit transmission is met. In addition, when one of the first transmitting tube Q1 and the second transmitting tube Q2 breaks down, the other transmitting tube can still amplify the signal, the output of the subsequent signal is not affected, and the stability of the whole circuit is greatly improved.

Further, the signal processing circuit 1 adopts an FPGA chip with the model of EPC 1441.

Further, the frequency synthesizer 4 includes a DDS chip, as shown in fig. 6, which is a schematic circuit diagram of the DDS chip, and the DDS chip is connected to the output end of the FPGA chip. The DDS chip is composed of a reference crystal oscillator, a phase frequency detector, a loop filter, a voltage-controlled oscillator, a frequency divider and the like. The reference frequency of the phase discriminator in the phase-locked loop is obtained by M frequency division of the crystal oscillator, the feedback signal of the voltage-controlled oscillator is sent to the phase discriminator through the variable frequency divider for phase comparison, and the output error signal of the phase discriminator is sent to the control end of the voltage-controlled oscillator through the loop low-pass filter.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.