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Re: [Discuss-gnuradio] USRP Audio Rate versus Sample Rate of Soundcard
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] USRP Audio Rate versus Sample Rate of Soundcard |
Date: |
Wed, 13 Feb 2008 08:17:03 -0800 |
User-agent: |
Mutt/1.5.17 (2007-11-01) |
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