基于DSP的数字复合频率计设计

摘要

介绍了一种基于DSP的复合频率计设计方案.通过对其内部的AD单元、SCI单元、EV单元、PWM单元及外围电路的设计,复合频率计可实现对信号的叠加、幅值和频率的测量及重建输入波形的功能,并将结果通过PC机来显示.本设计的算法思想是在进行多次采样后,对其进行FFT变换以使信号进行分离.经过实验结果验证:幅值的测量误差范围在3.5%以内,频率的测量误差范围为0.1%以下,满足了设计要求.%The paper introduces the design of digital compoundfrequency meter based on DSP. The digital compound frequency meter can realize the mixing of the two input signal、the frequency and amplitude measurement、the rebuilding of input signal by using its AD unit、SCI unit、EV unit、PWM unit and peripheral circuit. The result of measurement will be displayed on PC. The thought of algorithm is that FFT algorithm is used to separate the mixed signal after repetitious sampling.The experimental results verify that the measurement error of amplitude is within 3. 5％ and the measurement error of frequency range is within 0. 1％, which meet requirements of the design.