Thanks Marcus for your valuable information . Now as per you have said that the usrp/gnuradio doesnt do any default demodulation , that means if i apply a demodulation technique to the captured file from usrp_rx_cfile.py , i will get the required output.For example if i apply GMSK demodulation to the captured file i ll get the properly formatted output as per the GSM protocol ... right. Thanks
On Thu, Apr 7, 2011 at 10:02 PM, Marcus D. Leech <mle...@ripnet.com> wrote: > On 07/04/2011 10:34 AM, ton ph wrote: > >> Hi guys , >> I Just want to confirm a thing regarding the demodulation of the digital >> dat in the gnuradio as the signals are received from the usrp. The doubt >> are, >> 1. Where is the demodulation is implemented in the gnuradio . >> 2. What demodulation is implemented by default in the urp_rx_cfile ... >> please do help me someone in clearing my doubts . >> >> Thanks >> > Gnu Radio is a generic digital-signal-processing framework. Which includes > *many* pre-built processing blocks, including demodulators > and modulators, correlators, detectors, etc, etc. > > There is no *default* demodulation scheme anywhere in the basic > architecture, and usrp_rx_cfile is used to simply copy samples as they > come off the USRP hardware into a file. > > The USRP hardware doesn't do any demodulation--the signal you see delivered > to the host PC is just filtered/decimated baseband > samples as they come off the ADC, appropriately scaled for use inside Gnu > Radio. The USRP hardware doesn't know anything > about modulation or demodulation, per se. All of that is the > responsibility of the host software. Correspondingly, the transmit > side of the USRP hardware doesn't *know* anything about modulation, > either. It is entirely up to the host software to provide > appropriately-modulated samples for the hardware to dutifully turn into > analog signals and then (usually) up-convert to the > desired RF band of interest. Generally, the host interface operates in > "baseband" mode--the (complex) samples are centered at DC. > > Cheers > > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > -- Phenomenon # Life is the most precious phenomenon ever happen ... # Lets pray and give emotional strength to the innocent brave victims of japan # they are human and m also a human which implies we are one.
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