Aliasing on purpose? On Thu, Feb 12, 2015 at 11:25 AM, Marcus D. Leech <[email protected]> wrote: > On 02/11/2015 06:15 PM, Tommy Tracy wrote: > > I am using a USRP1, and I'm trying to receive FM radio. I'm using a BasicRX > daughterboard with a 0-250MHz range. The USRP itself has a LO frequency of > 64MHz. Does this limit my frequency range to 0-32MHz, or can I get into the > 100MHz range by somehow multiplying that Local Oscillator frequency? > > I get the following error: > > -- Opening a USRP1 device... > -- Using FPGA clock rate of 64.000000MHz... > -- Tune Request: 102.900000 MHz > -- The RF LO does not support the requested frequency: > -- Requested LO Frequency: 102.900000 MHz > -- RF LO Result: 0.000000 MHz > -- Attempted to use the DSP to reach the requested frequency: > -- Desired DSP Frequency: -102.900000 MHz > -- DSP Result: 25.100000 MHz > -- Successfully tuned to -25.100000 MHz > > -- > -- > Sincerely, > Tommy James Tracy II > Ph.D Candidate > Computer Engineering > University of Virginia > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > You might be better off getting a TVRX2 card for it. > > You're limited on the USRP1 to 64Msps, and since the BASIC_RX does no > downconversion--it's just an ADC "buffer", you'd be limited to <= 32MHz in > the > first Nyquist zone. > > You *could* put a very stiff FM-band-only filter and some gain in front of > the BASIC_RX, and calculate the appropriate "Nyquist folding" for your > desired > frequencies, and tune to those frequencies in the DC-32Mhz region. > > > > -- > Marcus Leech > Principal Investigator > Shirleys Bay Radio Astronomy Consortium > http://www.sbrac.org > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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