Re: [Discuss-gnuradio] I&Q Sampling

[Matt Ettus]

paul munro wrote:

>  How does the USRP do its quadrature sampling??
>
>  There seems to be many differing methods of achieving this. Some
>  suggest the the ADC's are off set by 90 deg,

There are 2 ADCs, one samples the I channel, one samples the Q channel.  The

>  others that the samples are multiplied by a series of 0,1,0.-1 and
>  1,0,-1,0 (which seems a waste of samples).

This is a way of using one adc to sample a real bandpass signal and then 
translate it to complex baseband.

Matt