Re: [Discuss-gnuradio] Guide : what is the value of the IF converted before feeding the ADC in usrp/gnuradio

[Marcus D. Leech]

On 04/12/2011 04:44 AM, ton ph wrote:
> Hi everyone ,
>  I would like to know what is the actual last converted IF frequency
> which is actually fed to the ADC in usrp/gnuradio , since ADC rate is
> 64MS/s , I hope it IF should be less than 2xSampling rate of ADC,
> which implies IF could not be 70Mhz. So what is the value of IF before
> entering the ADC and what speed rate does the baseband is fed to the
> ADC for samping.
> Thanks in advance and also i apologize for any errrormatic information
> in my post.
>
It depends on the daughtercard in use, but most daughtercards
down-convert the desired center
  frequency to a complex baseband, centered at 0Hz.

There are execeptions.  The original TV_RX used an IF of 5.75MHz, which
was converted to complex
  baseband (I and Q) in the FPGA with a DDC.




-- 
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org