Design of Periodic Signal Measurement and Analysis Device Based on Analog Preprocessing and FPGA Parallel Processing

Abstract

Combining analog preprocessing with FPGA parallel signal analysis, this paper implements a device for time domain and frequency domain measurement of periodic signals. The system consists of amplifying circuits, a 7 order Butterworth low pass filter, a 14 bit ADC chip Zynq 7020 and a serial port screen, and adopts analog digital joint filtering to improve anti interference performance. Through front end signal conditioning and digital calibration, the peak to peak input range reaches 0 500 mV with measurement error controlled within 5 mV. A 121 order FIR filter equalizes the analog passband, achieving simulation residual error less than 0.02 dB within 0 500 kHz passband and about 53.9 dB digital attenuation at 1 MHz. In the time domain branch, true RMS value is calculated and 1 or 3 cycles of waveform can be displayed. In the frequency domain branch, 4096 point FFT with Hann window is utilized for spectrum analysis, and the practical frequency error is basically within 10 Hz. Test results demonstrate that the proposed device features wide measurement range, high precision and strong anti interference capability, and can stably complete multi parameter measurement and analysis for periodic signals.