Re: [Discuss-gnuradio] Testing Whether USRP Can Transmit

[Eric Blossom]

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

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

> 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

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


> 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?

usrp_siggen.py

Eric