Hi Josh, on the SMA connectors I had connected my transmit receive
antennas. I wanted to know if while transmitting and receiving signals
using USRP sink and source blocks, can I silmatenously probe any pin on
the transmit/receive daughter board inorder to see the signal out and in
to USRP. Also I was trying to make an OFDM system by implementing the
following blocks:
Random Source:---->OFDM Modulator:------------>USRP Sink
[Minimum=0;Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â [ Modulation:8 QAMÂ Â Â Â Â Â Â Â Â Â Â Â Â Â [Unit
Number=0
Maximum=2;Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â FFT Length=512Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
Interpolation=400
Num Samples=1MÂ Â Â Â Â Â Â Occupied tones: 200Â Â Â Â Â Â Â Â Â Â Frequency=100M
Repeat=Yes]Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â CP Length: 128Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Gain=0
                                     Pad for USRP=Yes            Â
Side=Side A]
                                     Payload length=0]
After running this, when I probed pin tx0 - tx7 on the daughter board, I
was able to see some waveforms on the scope. But when I build the
receiver system:
USRP Source:----------->OFDM DeModulator:------------>FFT Sink
[Unit Number=0Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â [ Modulation:8 QAMÂ Â Â Â Â Â Â Â Â Â Â Â Â Â
Decimation=400Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â FFT Length=512Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
Frequency=100MÂ Â Â Â Â Â Â Â Â Â Â Â Â Occupied tones: 200Â Â Â Â Â Â Â Â Â
Gain=0 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â CP Length: 128Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
Side=Side AÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
RX Antenna=RXA ] Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
I am get the following warning:
"** (python:4085): WARNING **: IPP request failed with status 1030
      Timeout "
and now if i probe the same pins on the daughter board, I am not able to
see any waveforms. Can you please help me to figure out this behaviour.
Thanks & Rgards,
Somya A.
— On Tue, 14/4/09, Josh B. [email protected] wrote:
From: Josh B. [email protected]
Subject: Re: [Discuss-gnuradio] USRP Basics questions
To: [email protected]
Cc: “‘[email protected]’” [email protected]
Date: Tuesday, 14 April, 2009, 9:57 AM
Somya A. wrote:
HI Josh, we have basic TX , RX daughter board with us. also what is that
range you have mentioned into your reply is for?
Many times, users give the usrp sink numbers between +/- 1.0 and there
is no
transmit power. Just to double check, you should be giving usrp numbers
around
+/- 10e3
As far as how you can see the signal:
You can hook up an oscilloscope to one of the SMA connectors on the
basic TX
(TXA or TXB)
Or, connect the basic RX to the basic TX with SMA to SMA connector, and
use a
program like usrp_oscope.py or usrp_fft.py to look at the received
signal.
-Josh
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