Sample_Low_Pass.zip_LOW_Low Pass

clc clear all t=-0.06:0.01:0.06; carrier=sin(2*pi*8.*t); subplot(2,2,1) plot(carrier); t=-0.12:0.01:0.12; %signal=sin(2*pi*4.*t); %signal=[ -1*ones(1,9) ones(1,9) -1*ones(1,9) ] %signal=randn(1,26); randomsig = random('Normal',0,1,1,25); a=0.8; k1=a; d0=sqrt(1-k1.^2); n=1:10; h(n)=d0*(-a).^n; signal=conv(h,randomsig); subplot(2,2,2); plot(signal); both=[]; for i=1:length(signal) y =carrier.*signal(i); both=[both y]; end subplot(2,2,3); %AM Modulated Signal........ plot(both); noise=rand(1,length(both)); both=both+noise; %demodulated=[]; %for i=1:length(signal) % y =(carrier.^2).*signal(i); % demodulated=[demodulated y]; %end k=1;cos2sig=[];var=[]; for i=1:length(signal) j=i*length(carrier); sig=both(:,k:j); var=carrier.*sig; cos2sig=[cos2sig var]; k=j+1; end demodulated=cos2sig; %now use low pass filter at demodulatd signal to get data signal... [b,a]=butter(10,0.6,'low'); filtered_signal=filter(b,a,demodulated); k=1; for i=1:length(signal) j=i*length(carrier); sig=filtered_signal(:,k:j); k=j+1; filtered2(i)=mean(sig)*2; end subplot(2,2,2) hold on plot(filtered2,'red');