这是编写的farrow结构的滤波器的matlab仿真
matlab源程序如下:
- clc;close all;clear
- N = 29; % filter order, odd better
- L = N+1; % filter length;
- Npt = 256; % no. of frequency points for plots
- w = (0:1:Npt-1)/Npt; % frequenc scan (0,1)
- delay = [0 0.1 0.2 0.3 0.4 0.5]; % delay range x=0..0.5
- Nfil = length(delay); % number of filters
- h = zeros(1,L); % impulse response vector
- hvec=zeros(Nfil,L); % impulse response coefficient matrix
- magresp = zeros(Nfil,Npt);
- phasdel = zeros(Nfil,Npt-1);
- xvec=zeros(Nfil,1); % fractional delay vector
- P = 3; % polynomial order for FARROW structure (ca. 1-5)
- C=zeros(P+1,N+1); % polynomial coeff. matrix
- wp = 0.85; % normalized bandwidth (0-1.0)
- for i=1:Nfil
- d=delay(i);
- if d==0
- d=d+0.0000001; % avoid sin(0)/0;
- end
- xvec(i)=d;
- if (N/2-round(N/2))==0
- D=d+N/2;
- else
- D=d+N/2-0.5;
- end;
- cT=zeros(N+1,1);
- p1=cT;
- cT(1)=wp;
- if round(D)==D
- p1(1)=wp;
- else
- p1(1)=sin(D*wp*pi)/(D*pi);
- end;
- for k=1:N % compute the elements of the Toeplitz matrix (vector)
- kD=k-D;
- cT(k+1) =sin(k*wp*pi)/(k*pi);
- p1(k+1) =sin(kD*wp*pi)/(kD*pi);
- end;
- Pz=toeplitz(cT);
- h=Pz\p1;
- hvec(i,:)=h'; % store designed coeff. vector
- end
- for k=1:N+1
- cc=polyfit(xvec,hvec(:,k),P); % fit P:th-order polynomial to each coeff set
- C(:,k)=cc';
- end
- for j=1:Nfil
- d=delay(j);
- if d==0
- d=d+0.0000001; % add 0.001 to avoid sin(0)/0;
- end
- h = C(P+1,:); % coeffs. via pol. approximation
- for n=1:P
- h=h+d^n*C(P+1-n,:);
- end
- h=h/sum(h); % scale response at zero freq. to unity
- H = freqz(h,1,w*pi);
- magresp(j,:) = abs(H);
- uwphase=-unwrap(angle(H));
- phasdel(j,:) = uwphase(2:Npt)./(w(2:Npt).*pi); % avoid divide by zero
- end
- % figure(1);
- % for i=1:Nfil
- % plot(1:L,hvec(i,:),'k'); hold on
- % end;
- % xlabel('Time In Samples'); ylabel('Impulse Response');
- %
- % figure(2);
- % for i = 1:Nfil
- % plot(w,magresp(i,:),'k');hold on
- % end;
- % xlabel('Normalized Frequency'); ylabel('Magnitude');
- %
- % figure(3);
- % for i = 1:Nfil
- % plot(w(2:Npt),phasdel(i,:),'k'); hold on
- % end;
- % xlabel('Normalized Frequency'); ylabel('Phase Delay');
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
- Fs = 16; %采样频率
- T = 1 / Fs;
- F = 3.2; %信号频率
- N_Max = F*2^18; %采样点数
- f = F/Fs;
- n1 = 0:2:(N_Max-1);
- n2 = 1:2:(N_Max-1);
- %*******加时间失配*******%
- Time_Mismatch = [0,-0.01];
- %Time_Mismatch = [0 0 0 0];
- Data_in_1_Mismatch = awgn( cos(2*pi*f*(n1+Time_Mismatch(1))),100 );
- Data_in_2_Mismatch = awgn( cos(2*pi*f*(n2+Time_Mismatch(2))),100 );
- Data_in_1_Delay = 0;
- Data_in_2_Delay = 0;
- % for delay_test = Time_Mismatch(2)-0.1:0.01:
- for i = 0:P
- Data_in_1_Delay = Data_in_1_Delay + conv(C(P-i+1,:),Data_in_1_Mismatch)*(0.5*Time_Mismatch(1))^i;
- Data_in_2_Delay = Data_in_2_Delay + conv(C(P-i+1,:),Data_in_2_Mismatch)*(0.5*Time_Mismatch(2))^i;
- end
- for i = 0 : N_Max/2 + N - 1
- Data_in_Delay(2*i+1) = Data_in_1_Delay(i+1);
- Data_in_Delay(2*i+2) = Data_in_2_Delay(i+1);
- end
- for i = 0 : N_Max/2-1
- Data_in_Mismatch(2*i+1) = Data_in_1_Mismatch(i+1);
- Data_in_Mismatch(2*i+2) = Data_in_2_Mismatch(i+1);
- end
- figure(1)
- FFT_Analysis(Data_in_Mismatch,Fs)
- figure(2)
- FFT_Analysis(Data_in_Delay(end-2^15+1-50:end-50),Fs)
所有资料51hei提供下载:
Farrow.rar
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