[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Discuss-gnuradio] BasicRX boards and AM transmission
From: |
Martin Braun |
Subject: |
[Discuss-gnuradio] BasicRX boards and AM transmission |
Date: |
Mon, 10 Dec 2007 17:06:16 +0100 |
User-agent: |
KMail/1.9.5 |
Hi,
I'm still in the exploring phase of my GNU radio work and currently ran into
an annoying problem. All I want to do is transmit AM from one USRP to
another, which I thought would be the simplest RX/TX chain I could come up
with for a start.
However, I have not managed to get a clean AM reception with a USRP. I'm
pretty sure the tx component works, because I can listen to my transmission
with an old kitchen radio and it sounds fine.
RXing with the USRP simply doesn't work, though, neither with usrp_rx_nogui.py
nor with anything I could come up with. I get lots more noise than expected
and usually I get a very loud buzz or whistle which is a lot louder than the
TXed signal. Has anyone else had this problem?
I'm using the Basic* boards directly connected to an antenna (no bandpass
filtering). I realize this is not how the BasicRX is intended to be used, but
can this be the cause of a loud buzz or would it only create lots of extra
noise? Basically, is this a completely futile attempt?
I also tried the TVRX and then I sometimes get some spectral lines around
40kHz next to my main signal (this frequency doesn't occur anywhere in my RX
chain, it's audio at 32kS/s interpolated to 320kS/s for the USRP). My filters
on the TX chain seem OK, at least I haven't seen those spectral lines on an
(external) spectrum analyzer. Has anyone else ever seen lines like this?
Thanks for any help,
--
Martin Braun
Institut fuer Nachrichtentechnik
Universitaet Karlsruhe
http://www.int.uni-karlsruhe.de
- [Discuss-gnuradio] BasicRX boards and AM transmission,
Martin Braun <=