[Discuss-gnuradio] 4x RX chains on USRP1 with DBSRX2

[John Wilson]

Hi,

I'm wondering whether it's possible/how to use a USRP1 with 2x DBSRX boards to generate 4 separate streams via the 4rx usrp1 firmware. The required channels will be within the front end bandwidth of the DBSRX2.

At the moment I'm using a subdev spec of 'A:0 A:0 B:0 B:0' which I assume runs the signal from subdev A through RX chains 0 and 1, and subdev B through 2 and 3. Is this correct?

I am planning to set each daughter board to a frequency between its two frequencies of interest, then I'd like the DDCs to downconvert the data from the ADC independently to sit the two frequencies of interest in the centre of their respective baseband channels out of the USB bus. So can I change the DDC frequencies independently of the centre frequency in the daughterboard? Also what is the resolution of the DDS in the DDC, i.e. can I tune each one independently in ~1Hz steps?

Sorry if this has been asked before, I've been searching Google and the email lists all day and have not yet found an answer!

Thanks,

John