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List:       gnuradio-discuss
Subject:    Re: [Discuss-gnuradio] USRP with Basic_RX
From:       Johnathan Corgan <jcorgan () corganenterprises ! com>
Date:       2010-05-31 23:22:02
Message-ID: AANLkTilLV1PkKHXm3s-NsROOnrzZrmeApoiGUDJgQlQE () mail ! gmail ! com
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On Mon, May 31, 2010 at 15:03, Marcus D. Leech <mleech@ripnet.com> wrote:

> I set the tuning parameter of the source to 38.5MHz, and what I get on
> the FFT is a flat-line at =A0-410dB! =A0Now, granted, I don't have the in=
puts connected to anything
> yet, but I would expect there =A0to be *some* noise, and -410dB seems, we=
ll, like bad physics :-)

The Basic RX has no gain.  It's very likely your noise floor is either
below the LSB of the ADC, or the DDC is filtering the noise floor to
below the LSB of the filtered sample stream.  Add a file sink and look
at the actual sample values.

Or, try connecting something to the input :-)

Johnathan


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