Method and system for improving second and third harmonic indexes of output port

Abstract

The invention discloses a method and system for improving second and third harmonic indexes of an output port, and belongs to the technical field of electromagnetic fields and microwaves, and the method comprises the steps: S1, amplifying an input first excitation signal through a small signal amplifier, then extracting second and third harmonic signals, and outputting a second excitation signal; s2, preprocessing the output second harmonic signal and the output third harmonic signal; s3, performing broadband synthesis on the preprocessed second harmonic signal and the preprocessed third harmonic signal to output a dual-tone signal; s4, pre-processing the second excitation signal, outputting the pre-processed second excitation signal, and feeding the broadband synthesized dual-tone signal into the pre-processed second excitation signal; and S5, performing 180-degree phase offset on the second and third harmonics of the preprocessed second excitation signal through the dual-tone signal to obtain a third excitation signal, and outputting the third excitation signal to the antenna. Compared with a traditional method of adding filters, the method has the advantages that the transmitting power signal is increased by 0.4 dB; meanwhile, the efficiency index of the transmitter is improved, and the efficiency and reliability of the transmitter are improved.

Description

Technical Field

[0001] The invention relates to the field of electromagnetic field and microwave technology, and in particular to a method and system for improving the second and third harmonic indicators of an output port. Background Art

[0002] At present, the transmitters in the field of airborne integrated avionics equipment technology belong to multi-mode transmitters, and their functions and signal formats generally include aviation control, ADS-B, DME, TACAN, data link, etc. Among them, DME, TACAN, data link and other modes work in broadband, generally 960-1224MHz. The current multi-mode transmitters generally use GaN power amplifier tubes to realize the power amplification function, and the general port power index is in the order of 1000W~2000W. The current multi-mode transmitters generally use the method of adding filters to the final output port to improve the second and third harmonic indicators of the output power. The current multi-mode transmitters generally use the method of adding filters to the final output port to improve the second and third harmonic indicators of the output power. The cost is to increase the insertion loss at the back end of the output amplifier. Generally, a low-pass filter will increase the loss by 0.7dB, so that the second and third harmonic indicators of the port can be improved by more than 25dB. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method and system for improving the second and third harmonic indicators of an output port.

[0004] The objective of the present invention is achieved through the following technical solutions: In a first aspect, the present invention discloses a method for improving the second and third harmonic indicators of an output port, comprising the following steps: S1, input a first excitation signal, after the first excitation signal is amplified by a small signal amplifier, the second and third harmonic signals are extracted through the first second and third harmonic coupler, and then three signals are output, wherein the first channel outputs the second excitation signal, the second channel outputs the second harmonic signal, and the third channel outputs the third harmonic signal; S2, preprocessing the second harmonic signal output by the second channel and the third harmonic signal output by the third channel; S3, performing broadband synthesis on the pre-processed second and third harmonic signals to output a dual-tone signal; S4, after preprocessing the second excitation signal output from the first path, output it to the second, second and third harmonic coupler and the receiver respectively, and feed the broadband synthesized dual-tone signal into the second, second and third harmonic coupler; S5. Obtain a third excitation signal by performing 180° phase cancellation on the second and third harmonics of the preprocessed second excitation signal through a dual-tone signal, and output the third excitation signal to the antenna.

[0005] Based on the first aspect, the preprocessing described in step S2 includes amplification, filtering and phase shifting, the third harmonic signal is amplified by a third harmonic amplifier, the amplified third harmonic signal is filtered by a third harmonic bandpass filter, and then the filtered third harmonic signal is phase shifted by a third harmonic phase shifter; the second harmonic signal is amplified by a second harmonic amplifier, the amplified second harmonic signal is filtered by a second harmonic bandpass filter, and then the filtered second harmonic signal is phase shifted by a second harmonic phase shifter; wherein the second harmonic phase shifter and the third harmonic phase shifter use phase shift parameters within a preset range for phase shifting.

[0006] Based on the first aspect, the second harmonic phase shifter and the third harmonic phase shifter are controlled by a digital processing board.

[0007] Based on the first aspect, step S3 specifically includes: synthesizing the preprocessed second and third harmonic signals into one channel through a duplexer, and outputting a dual-tone signal, wherein the dual-tone signal includes a radio frequency signal of two frequency components.

[0008] Based on the first aspect, preprocessing of the second excitation signal outputted from the first path in step S4 includes: amplifying the second excitation signal in turn through a driving amplifier, outputting the amplified second excitation signal through an isolator, then amplifying the power of the second excitation signal to a target power through a final power amplifier, and then realizing directional transmission of the second excitation signal through a circulator, outputting one path to a receiver and another path to a second, second, and third harmonic coupler, and feeding a broadband synthesized dual-tone signal into the second, second, and third harmonic coupler.

[0009] Based on the first aspect, when the 180° phase cancellation is performed in step S5, the separated harmonic energy is absorbed and converted by the absorption load connected to the second, second and third harmonic coupler.

[0010] In a second aspect, the present invention discloses a system for improving the second and third harmonic indicators of an output port, which is used for a method for improving the second and third harmonic indicators of an output port as described in any one of the first aspects, comprising: a main amplifier link circuit, a phase shift conditioning circuit and a digital processing board, wherein the phase shift conditioning circuit is connected to the main amplifier link circuit and the digital processing board, and is used to pre-process the second harmonic signal output by the second path and the third harmonic signal output by the third path, and then perform broadband synthesis to output a dual-tone signal to the main amplifier link circuit; The main amplification link circuit is used to amplify the input first excitation signal to the target system power through a small signal amplifier, and then output the second excitation signal through first, second and third harmonic coupling, and after preprocessing the second excitation signal, output it to the antenna through second, second and third harmonic couplers; The digital processing board is used to store the second harmonic signal and the third harmonic signal after debugging preprocessing, read the second and third harmonic phase shift information, and control the second and third harmonic phase shifters.

[0011] Based on the second aspect, the main amplification link partial circuit includes: a small signal amplifier, a first, second and third harmonic coupler, a driving amplifier, an isolator, a final power amplifier, a circulator and a second, second and third harmonic coupler, the output end of the small signal amplifier is connected to the input end of the first, second and third harmonic coupler, the output end of the first, second and third harmonic coupler is connected to the input end of the driving amplifier, the output end of the driving amplifier is connected to the input end of the isolator, the output end of the isolator is connected to the final power amplifier, the output end of the final power amplifier is connected to the input end of the circulator, the output end of the ring road is respectively connected to the receiver and the second, second and third harmonic coupler, and the output end of the second, second and third harmonic coupler is respectively connected to the antenna and the circulator.

[0012] Based on the second aspect, the phase shift conditioning circuit includes: a third harmonic amplifier, a third harmonic bandpass filter, a third harmonic phase shifter, a second harmonic amplifier, a second harmonic bandpass filter, a second harmonic phase shifter, a second and third harmonic broadband power combiner and an absorption load, the input ends of the third harmonic amplifier and the second harmonic amplifier are respectively connected to the output ends of the first, second and third harmonic couplers, the output end of the third harmonic amplifier is connected to the input end of the third harmonic bandpass filter, the output end of the third harmonic bandpass filter is connected to the input end of the third harmonic phase shifter, the output end of the second harmonic amplifier is connected to the input end of the second harmonic bandpass filter, the output end of the second harmonic bandpass filter is connected to the input end of the second harmonic phase shifter, the output ends of the second harmonic phase shifter and the third harmonic phase shifter are connected to the second and third harmonic broadband power combiner, and the absorption load is connected to the second, second and third harmonic couplers.

[0013] Based on the second aspect, the digital processing board includes an embedded processor, the output end of the embedded processor is connected to the input ends of the second harmonic phase shifter and the third harmonic phase shifter, and the embedded processor includes FPGA, temperature sensor, FLASH and isolation driver.

[0014] The beneficial effects of the present invention are: 1) Compared with the traditional method of adding a filter, the present invention increases the transmission power signal by 0.4dB; at the same time, it improves the efficiency index of the transmitter, thereby improving the efficiency and reliability of the transmitter; 2) The second and third harmonic power is reduced by about 25dB, thus avoiding the use of high-loss filters to improve the second and third harmonic indicators of the output port. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1A schematic diagram of the steps of a method for improving the second and third harmonic indicators of an output port according to an embodiment of the present invention; Figure 2 The schematic diagram of a system for improving the second and third harmonic indicators of an output port according to an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0017] The present invention discloses a method for improving the second and third harmonic indicators of an output port. The method realizes that the transmitter couples out the second and third harmonics through a small input signal, and then passes through a phase shifter to synthesize a conditioning signal to form a second and third harmonic coupling signal with a phase difference of 180°, which is fed back to the output port of the power amplifier, so that the fundamental wave large signal of the output main line is not affected, and the second and third harmonic indicators are offset by about 25dB, thereby improving the second and third harmonic indicators. The advantage of this method is that it eliminates the need to design a low-pass filter at the output port, thereby eliminating the need to increase the loss of the transmission power signal by 0.7dB. Instead, a second and third harmonic coupler is designed, and the increase in the transmission power signal only increases the loss by 0.3dB. The efficiency and reliability of the transmitter can be greatly improved, and it has high economic value. The schematic diagram of the steps of the method described in the present invention is as follows Figure 1 As shown, the following steps are included: S1, input a first excitation signal, after the first excitation signal is amplified by a small signal amplifier, the second and third harmonic signals are extracted through the first second and third harmonic coupler, and then three signals are output, wherein the first channel outputs the second excitation signal, the second channel outputs the second harmonic signal, and the third channel outputs the third harmonic signal; S2, preprocessing the second harmonic signal output by the second channel and the third harmonic signal output by the third channel; S3, performing broadband synthesis on the pre-processed second and third harmonic signals to output a dual-tone signal; S4, after preprocessing the second excitation signal output from the first path, output it to the second, second and third harmonic coupler and the receiver respectively, and feed the broadband synthesized dual-tone signal into the second, second and third harmonic coupler; S5. Obtain a third excitation signal by performing 180° phase cancellation on the second and third harmonics of the preprocessed second excitation signal through a dual-tone signal, and output the third excitation signal to the antenna.

[0018] Exemplarily, a first excitation signal is input in step S1, and after the first excitation signal is amplified by a small signal amplifier, the second and third harmonic signals are extracted through the first second and third harmonic coupler, and then three signals are output, wherein the first channel outputs the second excitation signal, the second channel outputs the second harmonic signal, and the third channel outputs the third harmonic signal; at this time, when the fundamental frequency of the first excitation signal is 1 GHz, the second harmonic of 2 GHz and the third harmonic of 3 GHz can be extracted, and the power is: the second harmonic of 2 GHz is about 0 dBm, and the third harmonic of 3 GHz is about -10 dBm.

[0019] Exemplarily, the preprocessing described in step S2 includes amplification, filtering and phase shifting, the third harmonic signal is amplified by a third harmonic amplifier, the amplified third harmonic signal is filtered by a third harmonic bandpass filter, and then the filtered third harmonic signal is phase shifted by a third harmonic phase shifter; the second harmonic signal is amplified by a second harmonic amplifier, the amplified second harmonic signal is filtered by a second harmonic bandpass filter, and then the filtered second harmonic signal is phase shifted by a second harmonic phase shifter; wherein the second harmonic phase shifter and the third harmonic phase shifter use a phase shift parameter within a preset range for phase shifting, the preset range is a range pre-set according to the working environment, and is not limited to a specific range. In this embodiment, the phase shift parameter obtains a specific range through circuit testing. The second harmonic power of 2GHz is about 22dBm, and the phase shift code is: 111000; and the phase shift code can be adjusted or fine-tuned by the harmonic suppression degree measured at the final port. The third harmonic power of 3GHz is about 12dBm, and the phase shift code is: 000111; and the phase shift code can be adjusted or fine-tuned by the harmonic suppression degree measured at the final port. The second harmonic phase shifter and the third harmonic phase shifter are controlled by a digital processing board.

[0020] Exemplarily, step S3 specifically includes: synthesizing the pre-processed second and third harmonic signals into one channel through a duplexer, and outputting a dual-tone signal, wherein the dual-tone signal includes a radio frequency signal of two frequency components. At this time, a duplexer with 2GHz and 3GHz as input ports and 2-3GHz as a broadband output port is used, so that the two channels of signals with frequencies of 2GHz and 3GHz, respectively, can be synthesized into a radio frequency broadband synthetic signal containing two frequency components; the synthesized signal is a dual-tone signal, wherein the first tone is the second harmonic of 2GHz, with a power of about 19dBm; the second tone is the third harmonic of 3GHz, with a power of about 9dBm.

[0021] Exemplarily, preprocessing the second excitation signal outputted from the first path in step S4 includes: amplifying the second excitation signal in turn through a driving amplifier, outputting the amplified second excitation signal through an isolator, then amplifying the power of the second excitation signal to a target power through a final power amplifier, and then realizing directional transmission of the second excitation signal through a circulator, outputting it to a receiver in one path and to a second, second, and third harmonic coupler in another path, and feeding the broadband synthesized dual-tone signal into the second, second, and third harmonic coupler.

[0022] Exemplarily, when 180° phase cancellation is performed in step S5, the separated harmonic energy is absorbed and converted by the absorption load connected to the second second and third harmonic coupler. From the output port test, the fundamental, second and third harmonic powers when no broadband synthesis is fed in are: the main wave power of 1GHz is about 60dBm, the second harmonic power of 2GHz is about 20dBm, and the third harmonic power of 3GHz is about 10dBm; from the output port test, after debugging the phase shift, the fundamental, second and third harmonic powers when broadband synthesis is fed in are: the main wave power of 1GHz is about 60dBm, the second harmonic power of 2GHz is about -5dBm, and the third harmonic power of 3GHz is about -25dBm; the second and third harmonic powers are reduced by about 25dB, which improves the purpose of the second and third harmonic indicators of the output port. Compared with the traditional method of adding filters, the transmission power signal is increased by 0.4dB compared with the traditional method. At the same time, the efficiency index of the transmitter is improved.

[0023] In the second aspect, the present invention discloses a system for improving the second and third harmonic indicators of an output port, and its principle diagram is as follows: Figure 2 As shown, a method for improving the second and third harmonic indicators of the output port described above includes: a main amplifier link circuit, a phase shift conditioning circuit and a digital processing board. The phase shift conditioning circuit connects the main amplifier link circuit and the digital processing board, and includes: a third harmonic amplifier, a third harmonic bandpass filter, a third harmonic phase shifter, a second harmonic amplifier, a second harmonic bandpass filter, a second harmonic phase shifter, a second and third harmonic broadband power combiner and an absorption load. The input ends of the third harmonic amplifier and the second harmonic amplifier are respectively connected to the output ends of the first, second and third harmonic couplers, the output end of the third harmonic amplifier is connected to the input end of the third harmonic bandpass filter, the output end of the third harmonic bandpass filter is connected to the input end of the third harmonic phase shifter, the output end of the second harmonic amplifier is connected to the input end of the second harmonic bandpass filter, the output end of the second harmonic bandpass filter is connected to the input end of the second harmonic phase shifter, the output ends of the second harmonic phase shifter and the third harmonic phase shifter are connected to the second and third harmonic broadband power combiner, and the absorption load is connected to the second second and third harmonic coupler.

[0024] It is used to pre-process the second harmonic signal output by the second channel and the third harmonic signal output by the third channel, and then perform broadband synthesis to output dual-tone signals to the main amplification link circuit; the second harmonic and third harmonic coupled from the first, second and third couplers of the small signal pass through the second harmonic amplifier, bandpass filter and the third harmonic amplifier, bandpass filter respectively to form the second and third harmonic signals with relatively single spectrum, and then pass through the corresponding phase shifters (the phase shifters are controlled by the digital processing board) respectively, and then through the broadband synthesizer to synthesize the two signals into the required cancellation signal, and feed them into the second, second and third harmonic couplers at the back end of the final amplifier to form the second and third harmonic cancellation signals for the main signal.

[0025] Specifically, the main amplification link partial circuit includes: a small signal amplifier, a first, second and third harmonic coupler, a driving amplifier, an isolator, a final power amplifier, a circulator and a second, second and third harmonic coupler. The output end of the small signal amplifier is connected to the input end of the first, second and third harmonic coupler, the output end of the first, second and third harmonic coupler is connected to the input end of the driving amplifier, the output end of the driving amplifier is connected to the input end of the isolator, the output end of the isolator is connected to the final power amplifier, the output end of the final power amplifier is connected to the input end of the circulator, the output end of the ring road is respectively connected to the receiver and the second, second and third harmonic coupler, and the output end of the second, second and third harmonic coupler is respectively connected to the antenna and the circulator. It is used to amplify the input first excitation signal to the target system power through a small signal amplifier, and then output the second excitation signal through the first, second and third harmonic coupling. After preprocessing the second excitation signal, it is output to the antenna after the second, second and third harmonic coupler; the input first excitation signal is amplified to about 25dBm through a small signal amplifier, and then amplified to the order of 100W through the first, second and third harmonic coupler and the driving amplifier, and input to the final power amplifier through the isolator, and then the final power amplifier amplifies the power to the order of 2500W, and then the signal is output to the antenna after the circulator and the second, second and third harmonic coupler, and the signal is also output to the receiver through the circulator.

[0026] Specifically, the digital processing board includes an embedded processor, generally an FPGA, and some conventional hardware such as a temperature sensor, FLASH, and an isolation driver; the second and third harmonic phase shift information obtained by debugging can be stored through FLASH, the second and third harmonic phase shift information can be read through FLASH, and the second and third harmonic phase shifters can be controlled through the isolation driver. The output end of the embedded processor is connected to the input end of the second harmonic phase shifter and the third harmonic phase shifter.

[0027] Exemplarily, compared with the conventional method of adding a filter, the present invention increases the transmission power signal by 0.4 dB. At the same time, the efficiency index of the transmitter is improved. At the same time, the second and third harmonic power are reduced by about 25 dB, thereby avoiding the purpose of using a filter with large loss to improve the second and third harmonic index of the output port. The present invention can also improve higher harmonics by coupling the 4th harmonic or even higher harmonics for conditioning.

[0028] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for improving the second and third harmonic indicators of an output port, characterized in that: The following steps are involved: S1, input a first excitation signal, after the first excitation signal is amplified by a small signal amplifier, the second and third harmonic signals are extracted through the first second and third harmonic coupler, and then three signals are output, wherein the first channel outputs the second excitation signal, the second channel outputs the second harmonic signal, and the third channel outputs the third harmonic signal; S2, preprocessing the second harmonic signal output by the second channel and the third harmonic signal output by the third channel; S3, performing broadband synthesis on the pre-processed second and third harmonic signals to output a dual-tone signal; S4, after preprocessing the second excitation signal output from the first path, output it to the second, second and third harmonic coupler and the receiver respectively, and feed the broadband synthesized dual-tone signal into the second, second and third harmonic coupler; S5. Obtain a third excitation signal by performing 180° phase cancellation on the second and third harmonics of the preprocessed second excitation signal through a dual-tone signal, and output the third excitation signal to the antenna.

2. A method for improving the second and third harmonic indicators of an output port according to claim 1, characterized in that: The preprocessing described in step S2 includes amplification, filtering and phase shifting. The third harmonic signal is amplified by a third harmonic amplifier, the amplified third harmonic signal is filtered by a third harmonic bandpass filter, and then the filtered third harmonic signal is phase shifted by a third harmonic phase shifter; the second harmonic signal is amplified by a second harmonic amplifier, the amplified second harmonic signal is filtered by a second harmonic bandpass filter, and then the filtered second harmonic signal is phase shifted by a second harmonic phase shifter; wherein the second harmonic phase shifter and the third harmonic phase shifter use phase shift parameters within a preset range for phase shifting.

3. A method for improving the second and third harmonic indicators of an output port according to claim 2, characterized in that: The second harmonic phase shifter and the third harmonic phase shifter are controlled by a digital processing board.

4. A method for improving the second and third harmonic indicators of an output port according to claim 3, characterized in that: Step S3 specifically includes: synthesizing the preprocessed second and third harmonic signals into one channel through a duplexer, and outputting a dual-tone signal, wherein the dual-tone signal includes a radio frequency signal of two frequency components.

5. A method for improving the second and third harmonic indicators of an output port according to claim 1, characterized in that: In step S4, preprocessing the second excitation signal outputted from the first path includes: amplifying the second excitation signal in turn through a driving amplifier, outputting the amplified second excitation signal through an isolator, then amplifying the power of the second excitation signal to a target power through a final power amplifier, and then realizing directional transmission of the second excitation signal through a circulator, outputting it to a receiver in one path and to a second, second, and third harmonic coupler in another path, and feeding the broadband synthesized dual-tone signal into the second, second, and third harmonic coupler.

6. A method for improving the second and third harmonic indicators of an output port according to claim 1, characterized in that: When the 180° phase cancellation is performed in step S5, the separated harmonic energy is absorbed and converted by the absorption load connected to the second, second and third harmonic coupler.

7. A system for improving the second and third harmonic indicators of an output port, used in a method for improving the second and third harmonic indicators of an output port as claimed in any one of claims 1 to 6, characterized in that: include: A main amplifying link circuit, a phase shift conditioning circuit and a digital processing board, wherein the phase shift conditioning circuit is connected to the main amplifying link circuit and the digital processing board, and is used to pre-process the second harmonic signal output by the second path and the third harmonic signal output by the third path, and then perform broadband synthesis to output a dual-tone signal to the main amplifying link circuit; The main amplification link circuit is used to amplify the input first excitation signal to the target system power through a small signal amplifier, and then output the second excitation signal through first, second and third harmonic coupling, and after preprocessing the second excitation signal, output it to the antenna through second, second and third harmonic couplers; The digital processing board is used to store the second harmonic signal and the third harmonic signal after debugging preprocessing, read the second and third harmonic phase shift information, and control the second and third harmonic phase shifters.

8. A system for improving the second and third harmonic indicators of an output port according to claim 7, characterized in that: The main amplification link partial circuit includes: a small signal amplifier, a first, second and third harmonic coupler, a driving amplifier, an isolator, a final power amplifier, a circulator and a second, second and third harmonic coupler. The output end of the small signal amplifier is connected to the input end of the first, second and third harmonic coupler, the output end of the first, second and third harmonic coupler is connected to the input end of the driving amplifier, the output end of the driving amplifier is connected to the input end of the isolator, the output end of the isolator is connected to the final power amplifier, the output end of the final power amplifier is connected to the input end of the circulator, the output end of the ring circuit is respectively connected to the receiver and the second, second and third harmonic coupler, and the output end of the second, second and third harmonic coupler is respectively connected to the antenna and the circulator.

9. A system for improving the second and third harmonic indicators of an output port according to claim 7, characterized in that: The phase shift conditioning circuit includes: a third harmonic amplifier, a third harmonic bandpass filter, a third harmonic phase shifter, a second harmonic amplifier, a second harmonic bandpass filter, a second harmonic phase shifter, a second and third harmonic broadband power combiner and an absorption load. The input ends of the third harmonic amplifier and the second harmonic amplifier are respectively connected to the output ends of the first, second and third harmonic couplers, the output end of the third harmonic amplifier is connected to the input end of the third harmonic bandpass filter, the output end of the third harmonic bandpass filter is connected to the input end of the third harmonic phase shifter, the output end of the second harmonic amplifier is connected to the input end of the second harmonic bandpass filter, the output end of the second harmonic bandpass filter is connected to the input end of the second harmonic phase shifter, the output ends of the second harmonic phase shifter and the third harmonic phase shifter are connected to the second and third harmonic broadband power combiner, and the absorption load is connected to the second, second and third harmonic couplers.

10. A system for improving the second and third harmonic indicators of an output port according to claim 9, characterized in that: The digital processing board comprises an embedded processor, the output end of the embedded processor is connected to the input ends of the second harmonic phase shifter and the third harmonic phase shifter, and the embedded processor comprises an FPGA, a temperature sensor, a FLASH and an isolation driver.

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