> rebuild signal from frequency domain to time domain tia sal22
>
> Greetings all
>
> I would like to rebuild a signal from the frequency domain
> can this be done using fft? If so does anyone have some
> example code?
>
> Here's what I have so far. I create/import a signal and plot
> using the time domain. Then I use fft to convert to
> the frequency domain and plot. What I want to do now is
> be able to convert from the frequency domain data back to the time
> domain. Then I'll be able to export the file as a wave file
>
> PS: I won't have an equation to work with because I'll be importing
> an audio file, and I'll be making changes when the signal is
> in the frequency domain.
>
> But at the moment I'm just trying to convert from the
> frequency domain back to the time domain. So the third plot
> when created would look just like the first plot in the time domain
> in the example below
>
>
> %time domain
>
> %create time domain
> Fs = 1000; % Sampling frequency
> T = 1/Fs; % Sample time
> L = 1000; % Length of signal
> t = (0:L-1)*T; % Time vector
> y = 0.7*sin(2*pi*50*t) + sin(2*pi*120*t);
>
> %frequency domain
> NFFT = 2^nextpow2(L); % Next power of 2 from length of y
> Y = fft(y,NFFT)/L;
> f = Fs/2*linspace(0,1,NFFT/2+1);
>
> subplot(2,1,1),plot(Fs*t(1:50),y(1:50))
> title('Signal ')
> xlabel('time (milliseconds)')
>
> % Plot amplitude spectrum.
> subplot(2,1,2),plot(f,2*abs(Y(1:NFFT/2+1)))
> title('Amplitude Spectrum of y(t)')
> xlabel('Frequency (Hz)')
> ylabel('|Y(f)|')
>
> tia sal22
>
> --
> _______________________________________________