Re: [Discuss-gnuradio] GRC + USRP2 + WBFM: synchronization problem?

[Marcin Szelest]

Wav file is recorded from FT857 receiver connected directly to
microphone input of PC. Thats why its 22050Hz.


When I connect USRP2 source to the GRC receiver (bottom part of
picture) I can receive FM broadcasting.
If I connect this GRC receiver to GRC transmitter, it works perfectly too.

Problem is that USRP2 sink connected to transmitter generates poor
signal. I don't think that problem is connected with sample rate. I've
got feeling that there is problem with synchronization between GRC and
USRP2 or USRP2 is shutting frequently.


Regards,
Marcin

2011/3/29 Tom Rondeau <address@hidden>:
> On Mon, Mar 28, 2011 at 3:23 PM, Marcin Szelest <address@hidden>
> wrote:
>>
>> Hello,
>>
>> I have created FM transmitter in GRC:
>> http://szelest.org/question/TX_RX.grc.png
>>
>> Unfortunately demodulated audio has poor quality and annoying
>> distortions. I have spent a lot of time on it without positive effect.
>> Here is how demodulated audio sounds like:
>> http://szelest.org/question/recorded.wav
>>
>> When I have created FM receiver in GRC (bottom part of the schematic),
>> demodulated audio sounds perfectly on my PC.
>> Any ideas?
>>
>> I'm using gnuradio3.3.0 + USRP2(with interpolation changed from 4 to
>> 2) + BasicTX + FT857D as hardware receiver.
>> GRC file: http://szelest.org/question/TX_RX.grc
>> input WAV: http://szelest.org/question/indiana.wav
>>
>> Regards,
>> Marcin SQ9DJJ
>
>
> You almost certainly have the sample rate set incorrectly somewhere. For
> instance, when I play the file, it tells me it's a 22050 Hz WAV file, so
> something is probably set incorrectly.
> Tom
>