基于matlab的costas环载波同步仿真,含仿真操作录像

clc; clear; close all; fs = 12e6; %采样频率 ts = 1/fs; num = 2.5e6; %数据长度 SNR = -15; real_fc = 3563000; %实信号频率 data = sin(2*pi*real_fc*(0:num-1)*ts+pi/4)+sqrt(10^(SNR/10))*randn(1,num); %科斯塔斯环的输入信号 fc = 3562800; %本地频率 n = fs/1000; %累积时间为1ms nn = [0:n-1]; nf = floor(length(data)/n);% 将输入数据分成1ms的多个数据块 wfc = 2*pi*fc; %本地信号 phi_prv = 0; temp = 0; frame = 0; carrier_phase = 0; phase = 0; %环路滤波器的参数 c1 = 153.7130; c2 = 6.1498; for frame=1:nf % 产生本地的sin和cos函数 expcol = exp(j*(wfc*ts*nn+phase)); sine = imag(expcol); cosine = real(expcol); x = data((1:n)+((frame-1)*n)); %将数据转换到基带 x_sine = x.*sine; x_cosine = x.*cosine; Q = sum(x_sine); %经过滤波器 I = sum(x_cosine); phase_discri(frame) = atan(Q/I); %得到锁相环的输入 %锁相环 dfrq = c1*phase_discri(frame)+temp; %经过环路滤波器 temp = temp+c2*phase_discri(frame); wfc = wfc-dfrq*2*pi; %改变本地频率 dfrq_frame(frame) = wfc; phase = wfc*ts*n+phase; %得到不同块的相位 end plot(dfrq_frame/(2*pi),'LineWidth',3); hold on plot([1:length(dfrq_frame)], real_fc*ones(size([1:length(dfrq_frame)])),'r','LineWidth',1); legend('锁相环跟踪','实际的载波频率'); grid mean_freq=mean(dfrq_frame/2/pi) p=abs(real_fc-mean_freq)/real_fc;