melanio wrote: > > Dears, > > In data sheet of Microtune 4937 DI5(or in other doc.), the IF > frequency of a tuner comes out to 5.75MHz. > > But according to it directly measures(pin17,18) with spectrum > analyzer, the IF frequency is 44MHz. >
Various versions of the tuner operate on different IF frequencies. The one you have is at 44 MHz. > Moreover, DDC values comes out to -20M if ‘usrp_fft.py’ is carried out. > > So the ADC is 64MSPS, I don’t know why DDC is -20M and why IF > frequency is 44MHz.. is it possible figure? > > I think 44MHz is so high(It is in contravention of the Nyquist > theorem) and I don’t know why DDC is -20M > > > If the ADC samples at 64 MHz, Nyquist is 32 MHz. In a bandpass sampled system, 44 MHz will appear at 20 MHz. We set the tuner for -20MHz to bring that 20 MHz down to zero. Matt _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
