Signal Seperation

GNU Radio
1

Hi,

Could somebody give me some tips and help on the following problem?
Really
appreciated!

The input signal is b1(t)sin(f1t) + b2(t)sin(f2t), where f1 and f2
are
close but different, and b1(t) and b2(t) are two different square waves
with different period.
After the USRP down coverts this wave to the baseband, the two modulated
sine waves are mixed. How could I extract b2(t) or b1(t) respectively?
I tried to used a baseband filter, but it seems not work well.

Thanks!

2

On Thu, Oct 13, 2011 at 08:51:40PM -0400, Raullen Chai wrote:

After the USRP down coverts this wave to the baseband, the two modulated sine
waves are mixed. How could I extract b2(t) or b1(t) respectively?

How close are they with respect to the period length of the square
waves? If they are easily separated ‘visually’ in an FFT of the duration
of one pulse, you should be fine with filtering. Try a different filter,
with steeper flanks. Don’t worry about doing something extreme, you will
only distort your phase which doesn’t seem important.

MB

I tried to used a baseband filter, but it seems not work well.

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