RE: [Discuss-gnuradio] Problem using benchmark_rx.py

[meggahertz]

Hello Tom,

Looking at your reply to this post, I am wondering how can we then transmit
at carrier frequency around 90-110 MHz? Would we have to use a different
daughterboard? I didn't have any problem transmitting an analog audio signal
over carrier frequency within board frequency range as well as any waveform
using usrp_siggen.py. However, using benchmark_tx.py I can't transmit any
data at carrier freq higher than 44MHz. What board or method you think can
let me do this?

Thank you,


Tom Rondeau wrote:
> 
> Tarun,
> 
> 
>> From: Tarun Tiwari [mailto:address@hidden 
>>
>> Thank you Tom,
>>
>> I did change the bit rate for Rx and used -v mode, but its still not
> working. Please see the output of program:
>>
>> Transmitter:
>> address@hidden ~]# ./benchmark_tx.py -f 100e6 --tx-amplitude=500 -M 2 -r
> 100e3 -v 
>> >>> gr_fir_fff: using SSE
>> bits per symbol = 1
>> Gaussian filter bt = 0.35
>> Using TX d'board A: Basic Tx
>> Tx amplitude     500.0
>> modulation:      gmsk_mod
>> bitrate:         100kb/s
>> samples/symbol:    4 
>> interp:          320
>> Tx Frequency:    100M
>>.......................................................
>>........................................................
>>.............................
>>
>>
>> Receiver: 
>> address@hidden ~]# ./benchmark_rx.py -f 100e6 -r 100e3 -v
>> >>> gr_fir_fff: using SSE
>> bits per symbol = 1
>> M&M clock recovery omega = 4.000000
>> M&M clock recovery gain mu = 0.050000
>> M&M clock recovery mu = 0.500000
>> M&M clock recovery omega rel. limit = 0.005000
>> frequency error = 0.000000
>> Using RX d'board A: Basic Rx
>> Rx gain:         10
>> modulation:      gmsk_demod
>> bitrate:         100kb/s
>> samples/symbol:    4 
>> decim:           160
>> Rx Frequency:    100M
>>
>>
>>
>> I am connecting the the two boards using cables using -32dB RF attenuator
> on each port of daughterboards.
>>
>> I am using Basic Tx and Basic Rx Boards.
> 
> That's what I thought. You can't transmit at 100 MHz with the Basic boards
> (DAC is 128 Msps; you can really only transmit up to 44 MHz). Cut it down
> to
> something like 20 MHz.
> 
>> Please advise me, if I need to do some changes in benchmark_rx.py
>> program.
> And meanwhile, can you tell me do we need to call any function between 
>>
>>    fg.start()        # start flow graph
>>    fg.wait()         # wait for it to finish 
>>
>> To debug the program, I tried printing something inside rx_callback
> subroutine, but I think rx_callback is not being called anywhere in the
> program, thats why I am > not able to see any printed output on screen. Am
> I
> right? I tried this one: 
>>
>>    def rx_callback(ok, payload):
>>        global n_rcvd, n_right
>>        (pktno,) = struct.unpack('!H', payload[0:2])
>>        n_rcvd += 1
>>        if ok:
>>            n_right += 1
>>        print "Hello Tarun\n"
>>        print "ok = %5s  pktno = %4d  n_rcvd = %4d  n_right = %4d" % (
>>                ok, pktno, n_rcvd, n_right)
>>
>>
>> but no result ....
>> Please advise me. 
> 
> The rx_callback function only gets called if a packet is seen, which means
> correlating with the access code, so unless you're receiving packets,
> you'll
> never enter this function. Hopefully the change in carrier frequency will
> fix it.
> 
> Tom
> 
> 
> 
> 
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> 
> 

-- 
View this message in context: 
http://www.nabble.com/Problem-using-benchmark_rx.py-tp7733803p16959770.html
Sent from the GnuRadio mailing list archive at Nabble.com.