clc
clear all
close all
T=0.1; %---脉冲重复周期
PRI=1/T; %---脉冲重复频率
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%按照定义式求解%%%%%%%%%%%%%%%%%%%%%%%%
N=8; %脉冲个数
NN=128
Frequency=[-NN/2:1:NN/2-1]/NN*PRI; %频率轴采样
x=[0:N-1]
for k=0:7
for n=1:length(Frequency)
if (Frequency(n)*T-k/N)==0
H(n)=1;
else
H(n)=sin(N*pi*(Frequency(n)*T-k/N))./sin(pi*(Frequency(n)*T-k/N))/N;
end
end
figure
plot(Frequency,20*log10(abs(H)))
grid on
ylim([-40 0])
xlabel('频率（Hz）');
ylabel('幅度响应(dB）');
title(strcat('第',num2str(k+1),'个滤波器的频率响应'))
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%OVER%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%直接对滤波器系数进行处理%%%%%%%%%%%%%%%%%%%%%%
N=8;
w=PRI*[0:N-1]*2*pi/N
x=ones(1,N);
fft_num=128;
Frequency=PRI*[-fft_num/2:fft_num/2-1]/fft_num;
for k=1:8
x=exp(1i*w(k)/PRI*[0:N-1]); %DFT系数向量e.^(-wk)
beta=fftshift(fft(x,fft_num))/N; %计算其频谱，等效于频率响应
figure
plot(Frequency,20*log10(abs(beta)),'k')
grid on
ylim([-40 0])
xlabel('频率（Hz）');
ylabel('幅度响应(dB）');
title(strcat('第',num2str(k),'个滤波器的频率响应'))
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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