Design and implementation of a five-channel high-precision phase difference measurement system

In the multi-channel receiving system, the consistency of the phase and amplitude of the hardware circuit has a great impact on the signal processing results at the back end. Therefore, it is very important to ensure the consistency of the phase and amplitude between multiple channels. The high-precision measurement of the phase and amplitude of each channel is the premise of adjusting the circuit parameters. In order to provide a reliable and accurate parameter adjustment basis for the phase and amplitude adjustment of multiple channels, a convenient, effective and high-precision five-channel phase and amplitude consistency measurement scheme is presented in this paper. Firstly, the hardware circuit of the five-channel receiving system is designed, including signal preprocessing module, phase modulation module, A/D sampling module, FPGA control module, network port data transmission module, etc. Secondly, based on the designed hardware circuit, the FPGA program of 5-channel high-speed data acquisition and transmission is programmed. With the help of the data of the designed measurement scheme, by adjusting the parameters of the all-pass filter of the phase modulation circuit, the mean phase difference between the five channels is controlled within 0.1°, and the amplitude consistency is controlled within ±0.1dB.