On Wed, May 27, 2009 at 9:18 PM, Firas Abbas <[email protected]> wrote: > > Hi, > >> On Wed, 5/27/09, Karthik <[email protected]> wrote: >> >> If you use usrp_c() source, then the real part of the complex values are the >> I values and the imaginary parts are Q values. They are each 16 bits. >> >> Karthik >> > > That is not correct. If you use usrp_c source, then I & Q each are 32 bits > (total complex is 64bits). However, if you use usrp_s, then each are 16 bits > (total complex is 32bits).. > > Best Regards, > > Firas >
Apologies for the wrong information. I don't mean to side track the original query, but I have a couple of questions. I found this in the FAQ. "Regarding the bandwidth, we can sustain 32MB/sec across the USB. All samples sent over the USB interface are in 16-bit signed integers in IQ format, i.e. 16-bit I and 16-bit Q data (complex) which means 4 bytes per complex sample. This resulting in a (32MByte per sec/4Byte) 8Mega complex samples/sec across the USB." So I guess here we are assuming that we are using usrp_s() ? Also, since the ADC only has 12bit precision, are the extra bits used to retain precision as we go through the CIC and Halfband filters? If I were to use the std_4rx_0tx.rbf and usrp_s() to receive 4 channels. Then am I correct in saying that I need to have a deinterleaver with 8 channels after the usrp_s() from which I will club channel 0 and 1 into a new complex stream (similarly for channel 2 and 3 etc) to get 4 complex streams? Thanks, Karthik _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
