Hello, I did some study on using poly phase for separating different channels in SDR systems and based on the paper that I read, I found that the out put of poly-phase filter +FFT is in time domain even thought that there is an FFT in the system. Am I wrong? Is there any document to show how to use poly phase filter for separating different channels in a real SDR system? Best regards
Seperating different channels using poly phase
Started by ●March 26, 2007
Reply by ●March 26, 20072007-03-26
"mans" <(use_my_name_here)-34@blueyonder.co.uk> wrote in message news:WnWNh.221609$1E3.88378@fe3.news.blueyonder.co.uk...> Hello, > > I did some study on using poly phase for separating different channels > in SDR systems and based on the paper that I read, I found that the out > put of poly-phase filter +FFT is in time domain even thought that there is > an FFT in the system. Am I wrong? Is there any document to show how to use > poly phase filter for separating different channels in a real SDR system?It sounds like there's some confusion. Polyphase is just an implementation, not a particular kind of filter from the filter design aspect or from the filter input/output aspect. You'd have to be a lot more specific to suggest the output of a system with FFT buried inside is a sequence in the time domain. Fred
Reply by ●March 26, 20072007-03-26
On Mar 26, 3:52 pm, "mans" <(use_my_name_here)-...@blueyonder.co.uk> wrote:> Hello, > > I did some study on using poly phase for separating different channels > in SDR systems and based on the paper that I read, I found that the out putWhat is SDR?
Reply by ●March 27, 20072007-03-27
"Fred Marshall" <fmarshallx@remove_the_x.acm.org> wrote in message news:35ydnZuftPEB3JXbnZ2dnUVZ_hudnZ2d@centurytel.net...> > "mans" <(use_my_name_here)-34@blueyonder.co.uk> wrote in message > news:WnWNh.221609$1E3.88378@fe3.news.blueyonder.co.uk... >> Hello, >> >> I did some study on using poly phase for separating different channels >> in SDR systems and based on the paper that I read, I found that the out >> put of poly-phase filter +FFT is in time domain even thought that there >> is an FFT in the system. Am I wrong? Is there any document to show how to >> use poly phase filter for separating different channels in a real SDR >> system? > > It sounds like there's some confusion. > Polyphase is just an implementation, not a particular kind of filter from > the filter design aspect or from the filter input/output aspect. > > You'd have to be a lot more specific to suggest the output of a system > with FFT buried inside is a sequence in the time domain. > > FredHello, Here are some refrences to some implimentation: http://slaac.east.isi.edu/presentations/retreat_9909/polyphase.pdf http://www.sundance.com/web/files/productpage.asp Regards
Reply by ●March 27, 20072007-03-27
On Mar 26, 7:31 pm, "julius" <juli...@gmail.com> wrote:> On Mar 26, 3:52 pm, "mans" <(use_my_name_here)-...@blueyonder.co.uk> > wrote: > > > Hello, > > > I did some study on using poly phase for separating different channels > > in SDR systems and based on the paper that I read, I found that the out put > > What is SDR?Software Defined Radio, I believe. Jason
Reply by ●March 27, 20072007-03-27
cincydsp@gmail.com wrote:> On Mar 26, 7:31 pm, "julius" <juli...@gmail.com> wrote: >> On Mar 26, 3:52 pm, "mans" <(use_my_name_here)-...@blueyonder.co.uk> >> wrote: >> >>> Hello, >>> I did some study on using poly phase for separating different channels >>> in SDR systems and based on the paper that I read, I found that the out put >> What is SDR? > > Software Defined Radio, I believe.What a stupid term! I don't need software to define it; I know what a radio is. Software implemented radio, maybe. Jerry -- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Reply by ●March 27, 20072007-03-27
>Hello, > > I did some study on using poly phase for separating different channels>in SDR systems and based on the paper that I read, I found that the output>of poly-phase filter +FFT is in time domain even thought that there is an>FFT in the system. Am I wrong? Is there any document to show how to usepoly>phase filter for separating different channels in a real SDR system? >No, you are correct. A good reference for this technique is, "Digital Receivers and Transmitters Using Polyphase Filter Banks for Wireless Communications," by Harris and Dick. Basically, the mixer that is used in a traditional chanellizer is moved to be after the filter, which is mathematically equivalent to an FFT.
Reply by ●March 30, 20072007-03-30
On Tue, 27 Mar 2007 08:45:28 -0400, Jerry Avins <jya@ieee.org> wrote:>cincydsp@gmail.com wrote: >> On Mar 26, 7:31 pm, "julius" <juli...@gmail.com> wrote: >>> On Mar 26, 3:52 pm, "mans" <(use_my_name_here)-...@blueyonder.co.uk> >>> wrote: >>> >>>> Hello, >>>> I did some study on using poly phase for separating different channels >>>> in SDR systems and based on the paper that I read, I found that the out put >>> What is SDR? >> >> Software Defined Radio, I believe. > >What a stupid term! I don't need software to define it; I know what a >radio is. Software implemented radio, maybe. > >JerrySDR is a pretty common term these days and does stand for Software Defined Radio. The idea is just that whatever software is running defines what type of radio it is, rather than having to swap cards in a chassis (or whatever) to get different capabilities. It's mostly a military application idea, but the idea and terminology have been moving into the commercial space for several years. Since the entire mod/demod are implemented in software (in the generic sense), the data rates are limited by the practical processing capability. It's a pretty good approach for low-rate tactical radios where a push-button software reload give a guy in the field the capability to talk/connect through different networks or different agencies/deployments/whatever. Eric Jacobsen Minister of Algorithms Abineau Communications http://www.ericjacobsen.org
Reply by ●March 30, 20072007-03-30
Eric Jacobsen wrote:> On Tue, 27 Mar 2007 08:45:28 -0400, Jerry Avins <jya@ieee.org> wrote: > >> cincydsp@gmail.com wrote:...>>> Software Defined Radio, I believe. >> What a stupid term! I don't need software to define it; I know what a >> radio is. Software implemented radio, maybe. >> >> Jerry > > SDR is a pretty common term these days and does stand for Software > Defined Radio. The idea is just that whatever software is running > defines what type of radio it is, rather than having to swap cards in > a chassis (or whatever) to get different capabilities. It's mostly a > military application idea, but the idea and terminology have been > moving into the commercial space for several years.In other words, one swaps code, not card.> Since the entire mod/demod are implemented in software (in the generic > sense), the data rates are limited by the practical processing > capability. It's a pretty good approach for low-rate tactical radios > where a push-button software reload give a guy in the field the > capability to talk/connect through different networks or different > agencies/deployments/whatever.I understand the meaning. Like a lot of other jargon phrases, the actual words seem stupid when seen with a fresh eye. Jerry -- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Reply by ●March 31, 20072007-03-31
On Fri, 30 Mar 2007 12:52:50 -0400, Jerry Avins <jya@ieee.org> wrote:>Eric Jacobsen wrote: >> On Tue, 27 Mar 2007 08:45:28 -0400, Jerry Avins <jya@ieee.org> wrote: >> >>> cincydsp@gmail.com wrote: > > ... > >>>> Software Defined Radio, I believe. >>> What a stupid term! I don't need software to define it; I know what a >>> radio is. Software implemented radio, maybe. >>> >>> Jerry >> >> SDR is a pretty common term these days and does stand for Software >> Defined Radio. The idea is just that whatever software is running >> defines what type of radio it is, rather than having to swap cards in >> a chassis (or whatever) to get different capabilities. It's mostly a >> military application idea, but the idea and terminology have been >> moving into the commercial space for several years. > >In other words, one swaps code, not card. > >> Since the entire mod/demod are implemented in software (in the generic >> sense), the data rates are limited by the practical processing >> capability. It's a pretty good approach for low-rate tactical radios >> where a push-button software reload give a guy in the field the >> capability to talk/connect through different networks or different >> agencies/deployments/whatever. > >I understand the meaning. Like a lot of other jargon phrases, the actual >words seem stupid when seen with a fresh eye. > >JerryI won't disagree with that sentiment. ;) And for jargon I've been recently reminded of the Retroencabulator: http://video.google.com/videoplay?docid=5125780462773187994 which was apparently technology stolen from Chrysler's Turboencabulator: http://www.youtube.com/watch?v=pbVY5teBzlg My favorite part is that it's the same guy in the Retroencabulator vid as the second half of the Turboencabulator vid: http://www.plcdev.com/an_interview_with_mike_kraft Eric Jacobsen Minister of Algorithms Abineau Communications http://www.ericjacobsen.org
