Hi, I have an important suggestion:
The USRP ADC resolution is 12 Bits. These 12 Bits are converted to 32 bits (16 bits I and 16 Bits Q) after being processed by the FPGA DDC. However, if we reduced the output bit width of the DDC to 12Bit I and 12 Bit Q (or simply rotate right the resultant 16 bits I/Q by 4), then we packed and transfered the resultant 24 bits into a 3 bytes only (instead of 4 in the case of 16bit complex), then we can have an instantaneous bandwidth of 10.67MHz (32M/3) with 12 bits I/Q which is in my opinion will be optimum in the sense of ADC resolution and the obtained instantenouse bandwidth. Firas, Lisa Creer wrote: > > On 8/9/07, Johnathan Corgan <[EMAIL PROTECTED]> wrote: > >> It is possible to retain only the upper eight bits of each sample and >> pack these into two bytes such that the USB can carry 16 Msps complex; >> this gives you more passband bandwidth at the expense of dynamic range. > > > Now that I know it can be done, how do I retain the upper eight bits of > each > sample? > Is there code already written to do this? I'd like to maximize the > passband > bandwidth. > > Advanced applications of the USRP involve re-synthesizing the FPGA >> firmware and performing DSP operations directly on the samples coming >> from the ADCs before handing off the data to the USB. This >> theoretically gives you access to the entire 64 MHz receive bandwidth; >> however, there isn't a great deal of space on the FPGA for custom code, >> and the expertise/development time/debugging/pain involved is much >> higher than just using GNU Radio on the host. > > > I'll spare myself the pain and be content with a 16 MHz passband > bandwidth. > > You have been most helpful. Thank you. > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- View this message in context: http://www.nabble.com/USRP-data-rates-tf4240371.html#a12086929 Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio