Does that mean 8Mhz is the max. width of spectrum I can sense? But I remember reading on some post that we can sense spectrum upto +/-15MHz from the carrier frequency. (i.e. a chunk of 30 Mhz). Which one of the above is correct? What puts a limit on the maximum amount of spectrum we can sense?
Also, the in the program "usrp_spectrum_sense.py [options] min_freq max_freq", is there a limit on (max_freq - min_freq)? Thanks, Shravan. On 11/2/06, Johnathan Corgan <[EMAIL PROTECTED]> wrote:
On Thu, 2006-11-02 at 15:53 -0600, Shravan Rayanchu wrote: > I was going through some gnuradio documentation (on comsec.org wiki) > which says "...16-bit I and 16-bit Q data (complex), resulting in 8M > complex samples/sec across the USB (32 Mbps max. data rate). This > provides a maximum effective total spectral bandwidth of about > 6MHz...". > > By Nyquist criteria, should not this be 4 Mhz? This would be true for 8M *real* samples per second of a signal. However, when sampling in quadrature (complex sampling), you are creating 16M independent samples/second, and the Nyquist frequency is half that, or 8 MHz. I'm not sure where the 6 MHz reference comes from, except that that is also the IF bandwidth of the TV tuner module GNU Radio used to use (and the TVRX board that the USRP uses), so with these you'd get an "effective" spectral bandwidth of 6 MHz. -- Johnathan Corgan, AE6HO Corgan Enterprises LLC [EMAIL PROTECTED]
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