菜鸟之MATLAB学习——QPSK OQPSK信号生成及频谱分析

本人MATLAB学习小白仅做笔记记录和分享~~% qpsk oqpskclc;close all;Ts1;fc10;N_sample16;N_sum100;dt1/fc/N_sample;t0:dt:N_sum*Ts-dt;Tdt*length(t);d1sign(randn(1,N_sum));d2sign(randn(1,N_sum));gtones(1,fc*N_sample);%基本码元波形s1sigxpand(d1,fc*N_sample);s2sigxpand(d2,fc*N_sample);b1conv(gt,s1);b2conv(gt,s2);s1b1(1:length(s1));s2b2(1:length(s2));st_qpsks1.*cos(2*pi*fc*t)-s2.*sin(2*pi*fc*t);%QPSK波形s2_delay[ones(1,fc*N_sample/2),s2(1:end-fc*N_sample/2)];%% 重要st_oqpsks1.*cos(2*pi*fc*t)-s2_delay.*sin(2*pi*fc*t);%QPSK 与OQPSK原始信号波形subplot(421),plot(t,st_qpsk);xlabel(QPSK原始信号);axis([0,40,-2,2])subplot(422),plot(t,st_oqpsk);xlabel(OQPSK原始信号);axis([0,40,-2,2])%-----------将QPSK和OQPSK经过BPF--------------%bpf1sinc(2/Ts*t).*cos(2*pi*fc*t);st_bpf_qpskconv(st_qpsk,bpf1);st_bpf_qpskst_bpf_qpsk(1:length(st_qpsk));st_bpf_oqpskconv(st_oqpsk,bpf1);st_bpf_oqpskst_bpf_oqpsk(1:length(st_oqpsk));%QPSK 与OQPSK原始信号波形subplot(423),plot(t,st_bpf_qpsk);xlabel(QPSK经过低通滤波器后信号);axis([0,40,-40,40]);subplot(424),plot(t,st_bpf_oqpsk);xlabel(OQPSK经过低通滤波器后信号);axis([0,40,-40,40]);%----------------------end--------------------%%-----------QPSK和OQPSK经过BPF前频谱------------------%[f,sf_qpsk]T2F(t,st_qpsk(1:length(t)));[f,sf_oqpsk]T2F(t,st_oqpsk(1:length(t)));subplot(425),plot(f,abs(sf_qpsk));xlabel(QPSK经过滤波器前的频谱);hold on;subplot(426),plot(f,abs(sf_oqpsk),r--);xlabel(OQPSK经过滤波器前的频谱);%----------------------end--------------------%%-------------QPSK和OQPSK经过BPF后频谱-----------------%[f,sf_qpsk_lpf]T2F(t,st_bpf_qpsk(1:length(t)));[f,sf_oqpsk_lpf]T2F(t,st_bpf_oqpsk(1:length(t)));subplot(427),plot(f,abs(sf_qpsk_lpf));hold on;xlabel(QPSK经过滤波器后的频谱);subplot(428),plot(f,abs(sf_oqpsk_lpf),r--);xlabel(OQPSK经过滤波器后的频谱);%----------------------end--------------------%运行结果