dsss_match_filter.zip_dsss匹配滤波器_match_filter_匹配滤波器matlab仿真

clear;clc; tic; Rs = 800; over_samp_rate = 8; % connections = [1 0 1 1 0 0 0 0 0 0 0 0 1]; % connections = [0 1 0 0 1]; connections = [0 0 1 0 0 0 0 0 0 1]; mline = 1 - 2 * m_sequence(connections);% aa = repmat(mline,[1,5]);% bb= conv(mline(8192:-1:1),mline); spread_rate = length(mline); fs = Rs * over_samp_rate * spread_rate; % fc = 49.152e6; fc = 1.6384e6; EbN0 = 5.5; db = EbN0 - 10*log10(over_samp_rate * spread_rate)+10*log10(2);%-10*log10(1.22); % data_01 = [0 randint(1,3000)]; data_01 = zeros(1,100); data = 1 - 2 * data_01; data_num = length(data); % data_upsample = reshape(repmat(data,[spread_rate,1]),[1,data_num*spread_rate]); % base_band = data_upsample .* repmat(mline,data_num); baseband_data = conv(upsample(data,spread_rate),mline); baseband_data = baseband_data(1:data_num*spread_rate); shape = rcosfir(0.22,[-3,3],over_samp_rate,1,'sqrt'); baseband = conv(upsample(baseband_data,over_samp_rate),shape); baseband = baseband(1+3*over_samp_rate:data_num*spread_rate*over_samp_rate+3*over_samp_rate); IF_sig = baseband .* cos(2*pi*(1:length(baseband))*fc/fs); receive_if = IF_sig; % receive_if = floor(IF_sig./(max(abs(IF_sig))) .* 1638); % mean_receive_if = mean(receive_if .^ 2); receive_if = awgn(receive_if,db,'measured'); % receive_if = sqrt(5000/mean_receive_if) * receive_if; %% 正常接收 receive_demod = receive_if .* exp(-1j*2*pi*(1:length(IF_sig))*(fc+50)/fs); shape_filter = conv(upsample(mline,over_samp_rate),shape); shape_filter = shape_filter(length(shape):spread_rate*over_samp_rate); match_filter = conv(receive_demod,shape_filter(length(shape_filter):-1:1)); match_filter = match_filter(over_samp_rate * spread_rate-over_samp_rate * 3:data_num*spread_rate*over_samp_rate); downsample_match_filter = downsample(match_filter,over_samp_rate*spread_rate); recover = []; recover(1) = 0; for i = 1 : data_num-1 match_charge = downsample_match_filter(i); % match_charge_after = match_filter((i+1)*1023+561); match_charge_after = downsample_match_filter(i+1); if abs(match_charge + match_charge_after)> abs(match_charge - match_charge_after) recover(i+1) = recover(i); else recover(i+1) = mod((recover(i)+1),2); end end recover; recover_absolute = abs(recover(2:end)-recover(1:end-1)); error_num = sum(abs(diff(recover)) ~= abs(diff(data_01))); % pe = error_num / (data_num-1) % % % pe2 = berawgn(EbN0,'dpsk',2) pe2 = berawgn(EbN0,'dpsk',2) %% 非线性放大接收 % % baseband2 = reshape(repmat(baseband_data,[over_samp_rate,1]),[1,data_num*spread_rate*over_samp_rate]); % IF_sig2 = baseband2 .* cos(2*pi*(1:length(baseband2))*fc/fs); % % receive_if1 = floor(IF_sig2./(max(abs(IF_sig2))).*1638); % % % receive_if2 = log2(abs(receive_if1)); % % mean_receive_if2 = mean(receive_if1 .^ 2); % % receive_if2 = sqrt(5000/mean_receive_if2) * receive_if1; % % % receive_if2 = receive_if1; % % receive_demod2 = receive_if2 .* exp(1j*2*pi*(1:length(IF_sig))*fc/fs); % % % shape_filter = conv(upsample(mline,over_samp_rate),shape); % % shape_filter = shape_filter(length(shape):spread_rate*over_samp_rate); % match_filter2 = conv(receive_demod2,shape_filter(length(shape_filter):-1:1)); % match_filter2 = match_filter2(232:data_num*spread_rate*over_samp_rate); % downsample_match_filter = downsample(match_filter2,over_samp_rate*spread_rate); % % toc;