RE : [Discuss-gnuradio] PSK demodulation : g et exact point before deciding what is the closest constel lation point

[Christophe.Paring]

Thanks Eric !
 
I have a few questions more.
 
1- I've successfully retrieved the intermediate values by enabling logging to 
files. Though, I've no idea about how I "could just wire in your own logging 
stuff
wired in by reaching into the hier_block and connecting away", as an 
alternative way to reach the same results.
 
2- I am using USRP2 with an RFX2400 daughterboard. Datasheets indicate 17dBm 
for Transmit power, but I cannot find any information about Receive power. Does 
anyone know Input power for RFX2400 ?
 
3- I have only one USRP2 and would like to use a loop-back cable to connect the 
output to the input of the same USRP. So I would, for example, run benchmark_tx 
and benchmark_rx in two different shells. Can I do it without any worry ? I am 
asking the question because it seems that many people always ran a such test 
with two USRP (one for Tx and the second for Rx)
 
4- My last question refers to the error message "usrp2::tx_raw: FIXME: short 
packet: 1 items (32 bytes)" received when I run benchmark_tx with a modulation 
other than gmsk. This problem has been the subject of a couple of posts such as 
this one : http://osdir.com/ml/discuss-gnuradio-gnu/2009-06/msg00284.html . But 
it seems not to have been solved.
 
Thanks in advance for your help.
 
Chris  

________________________________

De: Eric Blossom [mailto:address@hidden
Date: lun. 22/02/2010 13:20
À: Paring, Christophe
Cc: address@hidden
Objet : Re: [Discuss-gnuradio] PSK demodulation : get exact point before 
deciding what is the closest constellation point



On Mon, Feb 22, 2010 at 12:03:28PM -0500, address@hidden wrote:
> Hi all !
> 
> I am dealing with PSK (BPSK, QPSK, 8PSK) modulation/demodulation ;
> in demodulation, I would want to retrieve the exact point (vector)
> before finding the closest constellation point.
K
> 
> Is there any way to get it with d?psk.py codes or whatever else ?
> 
> Thanks in advance for your help.
> 
> Chris

Chris,

If you look at the code
(gnuradio-core/src/python/gnuradio/blks2impl/dbpsk.py et al.), you'll
see that you can enable logging (and get all the intermediate values
logged to files) or you could just wire in your own logging stuff
wired in by reaching into the hier_block and connecting away.

Eric