Re: [Discuss-gnuradio] Source of annoying problem found

[Ian Wraith]

Hello Rob & Group

> I can only assume that you are using a frequency that is too high for
> the card. If the samplerate selected was, say 48kHz then your IF cannot
> be above 12kHz. Go do some reading on subjects like Nyquist frequency
> and aliasing for a better understanding.

 I should be OK Nyquist wise since I am sampling what is basically a
18 KHz waveform at 44.1 KHz. I had noticed my waveform amplitude was
varying before but in my last test this suddenly became much worse. I
now realise this was caused by me changing motherboards between these
tests. I suspect this new motherboard has a 11 KHz low pass filter
where as the old motherboard (another Asus but with a different sound IC)
had a low pass filter set at a much higher frequency.

Regards

Ian