Re: [Discuss-gnuradio] USRP Audio Rate versus Sample Rate of Soundcard

[Eric Blossom]

On Tue, Feb 12, 2008 at 09:33:11PM -0500, address@hidden wrote:
> Hello! 
> 
> I am current transmitting an audio stream from my sound card (SB Audigy2) to 
> the USRP and it is transmitting at an FM frequency. The problem I am facing 
> is that my sound card supports 44100Hz sample rate however, since the USRP 
> audio rate is an integer factor of 128MS/s When I receive the signal on a 
> regular FM radio it sounds funny depending on the audio rate I set (either 
> sounds high pitched if i set audio rate to high or sounds low pitched and 
> slow if I choose a lower sample rate). 
> 
> If I change the sample rate for the audio_source (sound card) it gives me an 
> error that the sound card requests 44100Hz.
> 
> I am including the lines I am using to rectrieve the audio data:
> 
> "         self.fg = gr.flow_graph()
>             src = audio.source(44100, options.audio_input)
>             fmtx = blks.wfm_tx(self.fg, self.audio_rate, self.usrp_rate)
>             self.fg.connect(src, fmtx, gain, self.u)"
> 
> Thank you for the previous help and Thanks for this one in advance.
> 
> Omer

If you're using alsa, try using  plughw:0,0 as the input device.
It's got a resampler built into it.

Eric