用窗函数法设计线性相位FIR低通滤波器。要求通带截止频率ωc=π/4，单位脉冲响应h(n)的长度N=23。绘出h(n)及其幅频响应特性曲线-Window function with linear phase FIR design a low pass filter. Required pass-band cutoff frequency ωc = π/4, unit impulse response h (n) of length N = 23. Plot h (n) and frequency

用Hanning窗设计线性相位滤波器，绘制幅频和相位特性曲线，并在改变N的值后观察N对滤波器特性的影响及其时域特点。-Hanning window with a linear phase filter design, drawing amplitude frequency and phase characteristic curve, and change the value of N, N were observed on the filter characteristics and time

stm32和ad9854制作的幅频相频曲线测试仪，matlab作为上位机显示特性曲线。-stm32 and ad9854 making amplitude-frequency phase frequency curve tester, matlab as a PC display characteristic curve.