CN-122026904-A - Self-checking and self-adjusting method for radio frequency microwave system

CN122026904ACN 122026904 ACN122026904 ACN 122026904ACN-122026904-A

Abstract

The invention discloses a self-checking self-adjusting method for a radio frequency microwave system, which relates to the technical field of radio frequency microwave systems and comprises the steps of inputting a frequency obtained through programmable N frequency division into a timing counter, outputting an actual sampling frequency, calculating the product of an ideal reference frequency and frequency multiplication times, then calculating the difference between a target frequency and the product to obtain a target sampling frequency, comparing the actual sampling frequency with the target sampling frequency, adjusting a frequency control word of a DDS to enable the frequency output by a phase-locked loop to be equal to the target frequency if the absolute value of the difference between the actual sampling frequency and the target sampling frequency is greater than or equal to the tuning resolution of the current DDS, and adjusting a DDS clock of the DDS to enable the frequency output by the phase-locked loop to be equal to the target frequency if the absolute value of the difference between the actual sampling frequency and the target sampling frequency is smaller than the tuning resolution of the current DDS. The invention ensures that the output low-phase noise signal has higher frequency and power accuracy, has simple circuit integral structure, is easy to debug, and can be self-diagnosed and self-optimized.

Inventors

Yue Maocai
ZHONG YUSHUAI
WANG TENG
HU XIAOJIE

Assignees

成都远望雷芯电子技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260409

Claims (7)

1. The self-checking self-adjusting method for the radio frequency microwave system comprises a controller, a DA/AD conversion circuit, a crystal oscillator, an amplifying power division circuit, a frequency multiplier, a mixer and a frequency division circuit which are sequentially connected, and further comprises a DDS, an analog phase discrimination circuit, a loop filter circuit, a voltage-controlled oscillator and a coupling detector which are sequentially connected, wherein the frequency multiplier is connected with the DDS, the mixer is connected with the analog phase discrimination circuit, the voltage-controlled oscillator is connected with the frequency division circuit, the controller is connected with the amplifying power division circuit, the DDS and the DA/AD conversion circuit, and the DA/AD conversion circuit is connected with the crystal oscillator, the voltage-controlled oscillator and the coupling detector. Acquiring a preset calibrated frequency-voltage mapping table, and acquiring tuning resolution of a DDS (direct digital synthesizer) in a radio frequency microwave system, an identification feedback frequency output by a mixer, an ideal reference frequency output by a crystal oscillator, a frequency output by a phase-locked loop, frequency multiplication times of a frequency multiplier and a target frequency set in a controller in real time, wherein the target frequency is set according to the calibrated frequency; After the feedback frequency of the output of the mixer is coupled, carrying out programmable N frequency division processing, inputting the frequency obtained by the programmable N frequency division processing into a timing counter, and outputting the actual sampling frequency; Calculating the product of the ideal reference frequency and the frequency multiplication times, and then calculating the difference between the target frequency and the product to obtain the target sampling frequency; Comparing the actual sampling frequency with the target sampling frequency; if the absolute value of the difference between the actual sampling frequency and the target sampling frequency is greater than or equal to the tuning resolution of the current DDS, adjusting the frequency control word of the DDS to enable the frequency output by the phase-locked loop to be equal to the target frequency; If the absolute value of the difference between the actual sampling frequency and the target sampling frequency is smaller than the tuning resolution of the current DDS, the DDS clock of the DDS is adjusted so that the frequency output by the phase-locked loop is equal to the target frequency.
2. The self-checking self-adjusting method for a radio frequency microwave system according to claim 1, wherein adjusting the DDS clock of the DDS to enable the output frequency of the phase-locked loop to be equal to the target frequency comprises reading a tuning voltage value corresponding to the target frequency from a calibrated frequency-voltage mapping table, generating a target tuning voltage signal by a digital-to-analog converter in a DA/AD (digital-to-analog) conversion circuit, inputting the target tuning voltage signal into a voltage-controlled oscillator or a crystal oscillator to generate a new low-frequency reference signal, sending the new low-frequency reference signal to a frequency conversion unit to output a new DDS clock, inputting the new DDS clock into the DDS to obtain a new phase-discrimination reference frequency, inputting the new phase-discrimination reference frequency into the phase-locked loop, and outputting the frequency equal to the target frequency by the phase-locked loop.
3. The self-checking and self-adjusting method for a radio frequency microwave system according to claim 2, wherein an adder is connected to an end of a loop filter circuit in the radio frequency microwave system, a target tuning voltage signal is generated by a digital-to-analog converter according to a tuning voltage value corresponding to a target frequency, the target tuning voltage signal is input into a voltage-controlled oscillator or a crystal oscillator, and a new low-frequency reference signal is generated, comprising: If the absolute value of the difference between the actual sampling frequency and the target sampling frequency is between the current tuning resolution of the DDS and the equivalent tuning resolution of the voltage-controlled oscillator after the trimming voltage is applied by the adder, adjusting the voltage of the adder according to the tuning voltage value corresponding to the target frequency by the digital-to-analog converter to generate a target tuning voltage signal, sending the target tuning voltage signal to the control end of the voltage-controlled oscillator, changing the tuning frequency step of the voltage-controlled oscillator, and generating a new low-frequency reference signal; If the absolute value of the difference between the actual sampling frequency and the target sampling frequency is smaller than the equivalent tuning resolution of the crystal oscillator after the trimming voltage is applied by the adder, adjusting the voltage of the adder according to the tuning voltage value corresponding to the target frequency by the digital-to-analog converter to generate a target tuning voltage signal, sending the target tuning voltage signal to the control end of the crystal oscillator, changing the tuning frequency step of the crystal oscillator, and generating a new low-frequency reference signal.
4. A self-test self-tuning method for a radio frequency microwave system as claimed in claim 3, wherein the tuning frequency step formula of the voltage controlled oscillator/crystal oscillator is changed to be : ; Wherein, the Is the tuning frequency step of the voltage controlled oscillator/crystal oscillator after modulation, TS is the tuning sensitivity of the voltage controlled oscillator/crystal oscillator, vcc is the supply voltage of the digital-to-analog converter, and N is the number of bits of the digital-to-analog converter.
5. The self-checking and self-adjusting method for a radio frequency microwave system according to claim 1, wherein adjusting the frequency control word of the DDS so that the frequency output by the phase-locked loop is equal to the target frequency comprises generating a new frequency control word from the target frequency, transmitting the new frequency control word to the DDS to obtain a new phase-identifying reference frequency, inputting the new phase-identifying reference frequency into the phase-locked loop, and outputting a frequency equal to the target frequency by the phase-locked loop.
6. The self-checking and self-adjusting method for a radio frequency microwave system according to claim 5, wherein the DDS output phase-discrimination reference frequency formula is : ; Wherein, the Is the phase discrimination reference frequency output by the DDS, Is the reference frequency of the crystal oscillator output, B is the frequency multiplication times, FTW is the frequency control word, A is the phase accumulator bit number.
7. The self-checking and self-adjusting method for a radio frequency microwave system according to claim 1, further comprising obtaining a preset power-voltage database, sending the detection level output by the coupling detector to an analog-to-digital converter in the DA/AD conversion circuit for level sampling, reading the voltage corresponding to the target power in the power-voltage database by the controller, generating a voltage signal corresponding to the target power by the digital-to-analog converter, and sending the voltage signal corresponding to the target power to the control end of the electrically-controlled attenuator to change the output power until the target power of the system is output.

Description

Self-checking and self-adjusting method for radio frequency microwave system Technical Field The invention relates to the technical field of radio frequency microwave systems, in particular to a self-checking and self-adjusting method for a radio frequency microwave system. Background Along with the continuous progress of communication technology, the requirements of a radio frequency microwave system on phase noise and frequency accuracy in actual work are gradually improved, the better the frequency accuracy is, the stronger the radar detection and imaging resolution is, the better the phase noise is, the dynamic range of the radar is improved, the higher the SAR high-resolution imaging accuracy is, the important breakthrough from 'discovery' to 'discrimination' can be realized, the self-checking can actively diagnose the state of equipment, the self-adjusting can actively optimize the state of the equipment, the self-checking and the self-adjusting are generally combined together to form a closed loop feedback and highly autonomous intelligent system, and the low-phase noise self-checking self-adjusting function is greatly applied to military and civil use. The frequency synthesizer of the common radio frequency microwave system is realized by three ways, namely direct frequency multiplication, a phase-locked loop and a DDS, wherein the direct frequency multiplication is limited by frequency adjustment and volume, the phase-locked loop is limited by phase noise, the DDS is limited by frequency upper limit, the conventional frequency synthesizer almost has no self-checking and self-adjusting function, the DDS is only used as a reference signal source, the output frequency of the DDS can not be dynamically calibrated during loop running once being set, and the DDS is difficult to meet high-requirement application. A self-test self-tuning method for a radio frequency microwave system has been developed to solve the above problems. Disclosure of Invention The invention provides a self-checking and self-adjusting method for a radio frequency microwave system, which aims to solve the problem that the existing frequency synthesizer hardly has the self-checking and self-adjusting function and is difficult to meet high-requirement application. The invention realizes the above purpose through the following technical scheme: The invention relates to a self-checking self-adjusting method for a radio frequency microwave system, which comprises a controller, a DA/AD conversion circuit, a crystal oscillator, an amplifying power division circuit, a frequency multiplier, a mixer and a frequency division circuit which are sequentially connected, and further comprises a DDS, an analog phase discrimination circuit, a loop filter circuit, a voltage-controlled oscillator and a coupling detector which are sequentially connected, wherein the frequency multiplier is connected with the DDS, the mixer is connected with the analog phase discrimination circuit, the voltage-controlled oscillator is connected with the frequency division circuit, the controller is connected with the amplifying power division circuit, the DDS and the DA/AD conversion circuit, and the DA/AD conversion circuit is connected with the crystal oscillator, the voltage-controlled oscillator and the coupling detector, and the self-checking self-adjusting method comprises the following steps: acquiring a preset calibrated frequency-voltage mapping table, and acquiring tuning resolution of a DDS (direct digital synthesizer) in a radio frequency microwave system, an identification feedback frequency output by a mixer, an ideal reference frequency output by a crystal oscillator, a frequency output by a phase-locked loop, frequency multiplication times of a frequency multiplier and a target frequency set in a controller in real time, wherein the target frequency is set according to the calibrated frequency; After the feedback frequency of the output of the mixer is coupled, carrying out programmable N frequency division processing, inputting the frequency obtained by the programmable N frequency division processing into a timing counter, and outputting the actual sampling frequency; Calculating the product of the ideal reference frequency and the frequency multiplication times, and then calculating the difference between the target frequency and the product to obtain the target sampling frequency; Comparing the actual sampling frequency with the target sampling frequency: if the absolute value of the difference between the actual sampling frequency and the target sampling frequency is greater than or equal to the tuning resolution of the current DDS, adjusting the frequency control word of the DDS to enable the frequency output by the phase-locked loop to be equal to the target frequency; If the absolute value of the difference between the actual sampling frequency and the target sampling frequency is smaller than the tuning resolution of the current DDS, the DDS clo