RE: [Discuss-gnuradio] unknown peak in the FFT-Plot Sink

[Paul Mathews]

Use an Intermediate Frequency (IF) and frequency translating filter. 
Paul Mathews

-----Original Message-----
From: Markus Feldmann [mailto:address@hidden 
Sent: Friday, March 20, 2009 5:06 AM
To: gnu radio mailing list
Subject: [Discuss-gnuradio] unknown peak in the FFT-Plot Sink


Hi All,

in all the examples and in my own gnuradio Programm, there
is an unknown Peak in the FFT-Plot sink.

Here is the Screenshot:
http://img257.imageshack.us/img257/8017/nochstrender.jpg

How to avoid this ?
Wherefrom does this come ?
I attach my Program to this mail, but i think it is still ok.

I need this to measure the power of the noise.

Further on you see the noise has a wave form always in
the middle of the FFT-Plot, still when i watch another spectrum. In the
gnuraio example from Eric Blossom this doesn't appear, but this example only
use a sin-signal-source not a usrp-source.

How to avoid this ?
I tried to change the decimation and the sample Rate,
but doesn't solved this.

Regards Markus