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[Discuss-gnuradio] Artefacts in usrp_fft.py
From: |
Luis Simoes |
Subject: |
[Discuss-gnuradio] Artefacts in usrp_fft.py |
Date: |
Fri, 30 Mar 2007 16:46:37 +0200 |
User-agent: |
KMail/1.8 |
Hi all,
We implemented a spectrum senser based on GnuRadio for our cognitive radio
research. In order to calibrate the senser we check the performance of the
RFX2400 and DBS RX d'board with the usrp_fft.py script. We use the norma FFT
and the waterfall plot of the script. Feeding the usrp with generated signals
by a high performance signal generator we could observe the appearance of
some strong artefacts in the spectrum. To find out the origin of this
artefacts we put a calibrated 50 ohm termination on the sma antenna connector
in order to assure we only measuring the noise floor of the usrp. Now we
could observe several artefact in almost all frequencies between 800 and 2500
MHz. Sometimes the artefacts are sharp peaks some times wider peaks and the
total number of peaks varies also from center frequency to center frequency.
Normally we use a decimation rate of 8 to sense a chunk of 8 MHz and we try
several gains of the d'board. If someone know how the origin of these
artefacts and/or how to avoid getting them in the sensed spectrum please
answer. Every advice will be appreciated. Thank you all in advance
Luis Simoes
- [Discuss-gnuradio] Artefacts in usrp_fft.py,
Luis Simoes <=