RE: [Discuss-gnuradio] Communication TEST

[Tom Rondeau]

Roberto

> -----Original Message-----
> From: address@hidden [mailto:discuss-
> address@hidden On Behalf Of Roberto
> Mastrodonato
> Sent: Friday, October 20, 2006 4:56 AM
> To: GNURadio Discussion List
> Subject: [Discuss-gnuradio] Communication TEST
> 
> Hi all
> 
> I've installed Gnuradio/USRP on the FC5 64 distribution and everything
> seems to work fine. I launch following examples:
> 
> ./test_usrp_standard_tx and get
> 
> tx_underrun
> xfered 1.34e+08 bytes in 4.2 seconds.  3.199e+07 bytes/sec.  cpu time =
> 0.028
> 1 underruns
> 
> then
> 
> ./test_usrp_standard_rx and get
> 
> xfered 1.34e+08 bytes in 4.19 seconds.  3.2e+07 bytes/sec.  cpu time =
> 0.032
> noverruns = 0
> 
> My daugtherboard is a flex2400. To test its goodness I launch:
> 
> ./benchmark_tx.py -f 2412000000.0 -v and I get
> 
> >>> gr_fir_fff: using 3DNow!
> bits per symbol = 1
> Gaussian filter bt = 0.35
> Using TX d'board A: Flex 2400 Tx
> Tx amplitude     12000
> modulation:      gmsk_mod
> bitrate:         500kb/s
> samples/symbol:    2
> interp:          128
> Tx Frequency:    2.412G
> ..............
> 
> and
> 
> ./benchmark_rx.py -f 2412000000.0 -v and I get
> 
> >>> gr_fir_fff: using 3DNow!
> bits per symbol = 1
> M&M clock recovery omega = 2.000000
> 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: Flex 2400 Rx
> Rx gain:         45
> modulation:      gmsk_demod
> bitrate:         500kb/s
> samples/symbol:    2
> decim:            64
> Rx Frequency:    2.412G
> 
> Besides, if I launch ./usrp_oscope.py -f 2.4G I get
> 
> ** (python:4994): WARNING **: IPP request failed with status 1030
> 
> ** (python:4994): WARNING **: IPP request failed with status 1030
> uO
> 
> with a windows showing the oscilloscope.
> 
> My question is: why if I launch ./benchmark_tx.py -f 2412000000.0 -v on a
> tx machine and /benchmark_rx.py -f 2412000000.0 -v on a rx machine, the rx
> one is not receiving anything? No packets!
> And if I launch /usrp_oscope.py -f 2.4G on the rx machine and then I
> generate 802.11b traffic at 1 Mbit, why am I not seeing any signal
> intensity variation on the oscilloscope?

Have you adjusted the vertical scaling? You'll also want to make sure you
set your center frequency on the channel you're transmitting on (2.412 MHz,
like you were using above).

Do you have a 802.11 access point nearby running on channel 1? It could be
causing interference to the GNU Radio signal (though I'd expect some packets
to still get through).

Do you have antennas connected, or are you doing it over cable? If cable,
are you attenuating it at all?

Do you have a spectrum analyzer of power meter that you can test to make
sure you're actually transmitting something?

> In the end, am I needed to pre-install particoular flex2400 firmwares
> before starting examples or those firmwares are directly loaded when I
> launch the examples?

No you don't have to do anything for this.

> Is it possible to get a clear description (scripts I mean) about creating
> communications between USRPs standing on different machines?
> 
> 10x a lot
> 
> Roberto
> 

Tom