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Re: [Discuss-gnuradio] Noise Leakage in transmission.


From: Mike Jameson
Subject: Re: [Discuss-gnuradio] Noise Leakage in transmission.
Date: Thu, 14 Mar 2013 18:21:35 +0000

Hi Sajjad,

>From a quick first glance without testing the flowgraphs on any
hardware i've noticed the following issues:

Corrections for both:

1) Your Tau and Max Deviation values are not the same.
2) you are sending data over TCP at 250e3 samp_rate to the server
which is expecting 50e3
3) lower the refresh rate on the Wx FFT to cut down on CPU usage

Tranceiver_Client Corrections:

1) 50e3 * 2.83447 is not 250e3. make the resample rate = 5 in your
polyphase arbritrary resampler.
2) Your low pass filter is decimating by 2 and should be 1

Tranceiver Server correcitons:
1) in your polyphase arbritrary resampler, you should make the number
of phases = 32 and then multiply the samp rate in the taps by 32 also.

Cheers,

Mike

--
Mike Jameson M0MIK BSc
Radio Communications Technology Specialist
Email: address@hidden
Web: http://www.scanoo.com


On 14 March 2013 17:26, Sajjad Safdar <address@hidden> wrote:
> HI,
> I have designed an server client Gnuradio companion programs to transmit
> pmr446 received channel. It then transmits it to server via TCP. Then the
> USRp transmit it over the air to channel 7 in PMr446 radio. But when the
> program runs a leakage noise adds up in the system. Can any one help out in
> this. The grc files are attached.
>
> Best Regards,
> SAJJAD SAFDAR
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>



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