Hello Munir, You may loose information if some operation, such as decimation which can increase the effective number of bits, was done in between the uint16 to 32 bit floating point and the conversion back to 16 bit integers. Most of the time the dynamic range of the samples isn't all signal though. If your received signal has noise, chances are very good that no actual signal information would be lost.
Regards, Derek On Wed, Jan 3, 2018 at 1:42 PM, Muhammad Munir <[email protected]> wrote: > Thank Kyeong Su Shin. > Is there any chance of loosing information if I convert complex data back > to 16bit as you suggested? I think it would loose information? > > Regards, > Munir > > On Wed, Jan 3, 2018 at 12:16 PM, Kyeong Su Shin <[email protected]> wrote: > >> Hello M.Munir, >> >> By default, USRP gives you data in 16bit integer format (x2, for I and >> Q). GNU Radio's complex data type uses IEEE754 single precision (x2, for I >> and Q). The data type is converted by UHD (the USRP driver). Each IEEE754 >> data point requires 32bit of storage (or memory, bandwidth, etc). This is >> why the data size is doubled. >> >> You can set the UHD block to output the raw int16 (interleaved) data, or >> you can convert back the GNU Radio's complex data type to a int16 based >> format and then send them over TCP (*make sure that you re-scale the I-Q >> data, as the complex data is normalized to [0,1] by UHD). >> >> Regards, >> Kyeong Su Shin >> >> On Wed, Jan 3, 2018 at 2:25 PM, Muhammad Munir <[email protected]> >> wrote: >> >>> Dear All, >>> I am confused to understand a behavior of GNURADIO USRP Source block. >>> The problem is, >>> 1. I connected USRP N200 with my PC. >>> 2. I set both the cahnnels of USRP >>> 3. I set the sampling rate of both as 5MHz >>> 4. I connected one channel directly to the Frequency Sink Block >>> 5. I connected the 2nd channel with TCP sink to transfer data of channel >>> 2 to the other PC. >>> 6. When I started the flow graph and checked for data rate on system >>> monitor, >>> I was receiving data at 40MBps and sending data was at 80 MBps. >>> Can anyone explain this behaviour? >>> Is it the issue with Gnuradio USRP source block? >>> I read a long before that UHD block gets samples from USRP and combine >>> two samples into single for comples output. If it is, then It should not >>> affect the data rate? >>> >>> Kind Regards, >>> M. Munir >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> [email protected] >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >> > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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