On 02/12/2013 04:03 PM, Marcus D. Leech wrote: >> >> On 02/12/2013 12:10 PM, John Wilson wrote: >>> 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? >> That seems 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 >> You will want a tune_request object where the rf_freq is set to the >> desired center frequency of the DBSRX (something in between that each >> CORDIC can shift away from). And set the rf freq policy to manual. >> >> There are some examples of making the tune request in the grc block for >> usrp source properties dialog box. >> >>> daughterboard? Also what is the resolution of the DDS in the DDC, >>> i.e. can >>> I tune each one independently in ~1Hz steps? >>> >> The CORDIC resolution is pretty much 64e6/(1<<32), so sub Hz. >> >> >> -josh >> > Also, will he need to use the 4rx FPGA image, or will UHD automagically > use the right image? > >
Its an args option, exact example here: http://files.ettus.com/uhd_docs/manual/html/usrp1.html#specify-a-non-standard-image -josh > _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
