Re: [Discuss-gnuradio] Help : Is this right that the daughterboard passes data to the usrp board in the I and Q format.

[Marcus D. Leech]

On 04/22/2011 01:54 AM, ton ph wrote:
>
> Hi guys ,
>     I am using DBSRX , now i am trying to trace the data flow in the
> usr-gnuradio . I see AD9862 ADC  in the usrp and some of the block
> diagrams , and i think that the daughterboard
> passes the analog signals to the ADC in the I and Q format . Please
> guide me if this is right or wrong ... Thanks .
>
That is precisely correct, yes.  Most daughterboards use an analog
quadrature mixer to produce
  a complex (I and Q) baseband signal.

The TV_RX is one that *doesn't* -- it's a conventional superheterodyne
receiver, with a final IF
  frequency of (as I recall) 5.75MHz, which is passed to a single ADC
channel, and the FPGA
  mixes it down to a complex baseband digitally using a digital
quadrature mixer.

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