H i Marcus, I got it. It is a case of bandpass sampling. .Thank you.
On Fri, Jul 5, 2013 at 6:12 PM, Marcus D. Leech <mle...@ripnet.com> wrote: > ** > On 07/04/2013 11:51 PM, Karan Talasila wrote: > > Hi Josh, > can you explain how and why the frequency translation > occurs? secondly when the same basic tx chip is used on a usrp N210, the > translation occurs at 50Mhz and after. So for USRP N210, the entire range > from 0-250 Mhz is represented by alternating between -50Mhz to +50Mhz. Why > is it that way? > > The BASIC_RX and LF_RX have no downconversion hardware in them at all. > They are basically just "buffers" for the ADCs. The BASIC_RX has an > analog reponse that starts to fall off at about 250Mhz, which is why > it's rated to 250Mhz. > > In the USRP1/B100/E1XX systems, the sampling clock is at 64MHz by > default. That means the first aliases start to show up at the 1st Nyquist > frequency of 32Mhz (half of sample rate). Similarly in the N2XX, which > a 100MHz sampling clock, those aliases start to show up at 50Mhz. > > My suggestion would be to look into so-called bandpass sampling, and also, > importantly, Nyquist Sampling Theorem. > > > -- > Marcus Leech > Principal Investigator > Shirleys Bay Radio Astronomy Consortiumhttp://www.sbrac.org > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- Regards Karan Talasila
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