matlab code for converting a bandpass spectrum to a low pass

[ashumtech]

Can anyone help me in writting a matlab code for converting a bandpass spectrum to a low pass.

 

[lebesgue]

If G(f-mfs) represents the band pass spectrum where m notequal to zero. Then g(t)= F^-1(G(f-m*fs)). Write out the integral expression for that using the definition of Fourier transform. Change the variable as p=f-m*fs. Obtain the integral in terms of low pass spectrum like integral of G(f)*e^(...)*e^(...)df . What do you understand from this? This is enough for getting an idea.

 

[kalyansrinivas]

You can do this by multiplying with exp(-j2*pi*f/fs*t) = by cos(2*pi*f/fs*t) for inphase and -j*sin(2*pi*f/fs*t) for quadrature phase than you can sum up them which gives a low pass signal

 

[ashumtech]

You can do this by multiplying with exp(-j2*pi*f/fs*t) = by cos(2*pi*f/fs*t) for inphase and -j*sin(2*pi*f/fs*t) for quadrature phase than you can sum up them which gives a low pass signal

please tell me what will be 't' in your reply as i am doing the processing in digital spectrum having some discrete values in 5-10 GHz range. Kindly help me in figuring this out.