2012/4/12 osama mohamed <osama_valencia...@hotmail.com> > hi all , > > about Nick's statement , > *Don't worry about the USRP native rate (64/128Msps). The FPGA inside the > USRP handles interpolation and decimation to step from the sample rate of > the USB interface (0.5Msps to 8Msps) to the ADC/DAC rate (64Msps/128Msps). > The sample rate you choose should be the sample rate that is appropriate > for your application*. > > i think this is correct provided that you consider that the interpolation > or decimation has a maximum value which is i think equal to 400 , > is this true Nick??? > regards , > Osama >
Yes, there are practical limits to the decimation/interpolation rates you can choose. In general, you want to pick an even decimation/interpolation, and in general, you want to pick a rate that is divisible by 4. This enables the use of both the halfband filters. Valid decimation/interpolation values range from 4 to 512. --n > > > > ------------------------------ > Date: Wed, 11 Apr 2012 09:23:35 -0700 > From: n...@ettus.com > To: javma...@gmail.com > CC: discuss-gnuradio@gnu.org > Subject: Re: [Discuss-gnuradio] Question about sampling rate > > > On Wed, Apr 11, 2012 at 9:14 AM, Javier Suarez <javma...@gmail.com> wrote: > > Hi... > I mean... the sampling rate of the uhd sink and source what refers to...? > I've since in some documents that if you are transmitting , you have to > take in account that the DAC for output works at 128 M/s and the sample > rate for the UHD sink block has to be determined somewhow from that. > > In the same way the ADC for reception works at 64 M/s and the sampling > rate for the UHD source block has to be determined somehow from that 64 M/s > . > > I just want to make simple transmission and reception. > > Am I wrong? or I am understanding not really good what I am reading about > this. Thanks in advance. > > > Don't worry about the USRP native rate (64/128Msps). The FPGA inside the > USRP handles interpolation and decimation to step from the sample rate of > the USB interface (0.5Msps to 8Msps) to the ADC/DAC rate (64Msps/128Msps). > The sample rate you choose should be the sample rate that is appropriate > for your application. > > --n > > > > > > > On Wed, Apr 11, 2012 at 10:58 AM, Nick Foster <n...@ettus.com> wrote: > > On Wed, Apr 11, 2012 at 8:53 AM, Javier Suarez <javma...@gmail.com> wrote: > > Hi everyone... > I am getting confused about the use of the parameter of sampling rate in > GNU RADIO. > I really need to understand the sampling rate of the uhd sink and source > and the sampling rate of the blocks in the flow graph and how to choose > those sampling rates. > > Thanks a lot for you help!! > > > Sample rate is a fundamental parameter of digital signal processing. Try > an introductory DSP textbook, or the following articles: > http://en.wikipedia.org/wiki/Discrete_signal > http://en.wikipedia.org/wiki/Sampling_rate > http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem > http://en.wikipedia.org/wiki/Sampling_(signal_processing) > http://en.wikipedia.org/wiki/Aliasing > > Without a basic understanding of sampling theory or DSP you will have > difficulty progressing with Gnuradio. > > --n > > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > > _______________________________________________ Discuss-gnuradio mailing > list Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
