Testing Whether USRP Can Transmit


#1

I am working with a USRP1. I eventually will want to transmit and
receive data packets between USRP1s, but right now I am getting to grips
with the system.

I am currently trying out the benchmark_tx, benchmark_rx programs.

I call benchmark_rx on my USRP1’s LFRX-LF daughterboard and leave it
running,

sudo python benchmark_rx.py -f 10M -R A --rx-gain=70 -v -r 500k -d 128

bits per symbol = 1
M&M clock recovery omega = 2.000000
M&M clock recovery gain mu = 0.175000
M&M clock recovery mu = 0.500000
M&M clock recovery omega rel. limit = 0.005000
frequency error = 0.000000

Receive Path:
Using RX d’board A: Flex 2400 Rx MIMO B
Rx gain: 70
modulation: gmsk_demod
bitrate: 250kb/s
samples/symbol: 2
decim: 128
Rx Frequency: 10M

I then call benchmark_tx on my USRP1’s LFTX-LF daughterboard,

sudo python benchmark_tx.py -TA -f 10M -r 500k -v --tx-amplitude=20000

gr_fir_fff: using SSE
bits per symbol = 1
Gaussian filter bt = 0.35
Using TX d’board A: Flex 2400 Tx MIMO B
Tx amplitude 20000.0
modulation: gmsk_mod
bitrate: 500kb/s
samples/symbol: 2
interp: 128
Tx Frequency: 10M

This prints out … etc signifying packets are apparently being
transmitted.

However when I flip over to the benchmark_rx console no packet
notifications are being displayed.

Is the USRP transmitting data? Why is it not receiving this data if it
is transmitting?

Furthermore is there a test/example program just for testing whether the
USRP is transmitting through its antenna? For instance a program that
gets the USRP to produce an audible tone out of its antenna?


#2

On Mon, Mar 02, 2009 at 02:59:40AM +0100, William Sherman wrote:

modulation: gmsk_demod
bitrate: 250kb/s
samples/symbol: 2
decim: 128
Rx Frequency: 10M

Note that your -d 128 is overriding your -r 500k, resulting in a
rx bitrate of 250kb/s. Leave out the -d option.

bitrate: 500kb/s
samples/symbol: 2
interp: 128
Tx Frequency: 10M

Since you’re using only the -r 500k option, you get the right answer,
500kb/s.

USRP is transmitting through its antenna? For instance a program that
gets the USRP to produce an audible tone out of its antenna?

usrp_siggen.py

Eric