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Need Help on Costas Loop for coherent GMSK demodulation

Started by richard_zhang May 12, 2008
Dear all,

I saw in google that costas loop can be used as the carrier recovery
mechanism for coherent GMSK signal demodulation, but I did not find any
detailed article about it. Can anybody give a good reference to implement
costas loop for gmsk? 

Any useful weblink or technical article will be appreciated. 



Richard
On May 12, 11:40 am, "richard_zhang" <hardhear...@yahoo.com.cn> wrote:
> Dear all, > > I saw in google that costas loop can be used as the carrier recovery > mechanism for coherent GMSK signal demodulation, but I did not find any > detailed article about it. Can anybody give a good reference to implement > costas loop for gmsk? > > Any useful weblink or technical article will be appreciated. > > Richard
There are some IEEE papers on this, here's one: Single-chip CMOS MSK coherent demodulator Suzuki, H.; Yamao, Y.; Kikuchi, H. Electronics Letters Volume 18, Issue 13, June 24 1982 Page(s):581 - 582 Digital Object Identifier 10.1049/el:19820393 The Costas loop for MSK is modified to include a third term in the multiplier which is a half bit rate clock. The clock and carrier recovery are coupled together. John
>On May 12, 11:40 am, "richard_zhang" <hardhear...@yahoo.com.cn> wrote: >> Dear all, >> >> I saw in google that costas loop can be used as the carrier recovery >> mechanism for coherent GMSK signal demodulation, but I did not find
any
>> detailed article about it. Can anybody give a good reference to
implement
>> costas loop for gmsk? >> >> Any useful weblink or technical article will be appreciated. >> >> Richard > >There are some IEEE papers on this, here's one: > >Single-chip CMOS MSK coherent demodulator >Suzuki, H.; Yamao, Y.; Kikuchi, H. >Electronics Letters >Volume 18, Issue 13, June 24 1982 Page(s):581 - 582 >Digital Object Identifier 10.1049/el:19820393 > >The Costas loop for MSK is modified to include a third term in the >multiplier which is a half bit rate clock. The clock and carrier >recovery are coupled together. > >John >
Hi John, Thanks for the information. I will try to find and read it. By the way, is it a reliable technique for GMSK demodulation? I want a technique which is able to practically work.
On May 13, 4:11 am, "richard_zhang" <hardhear...@yahoo.com.cn> wrote:
> >On May 12, 11:40 am, "richard_zhang" <hardhear...@yahoo.com.cn> wrote: > >> Dear all, > > >> I saw in google that costas loop can be used as the carrier recovery > >> mechanism for coherent GMSK signal demodulation, but I did not find > any > >> detailed article about it. Can anybody give a good reference to > implement > >> costas loop for gmsk? > > >> Any useful weblink or technical article will be appreciated. > > >> Richard > > >There are some IEEE papers on this, here's one: > > >Single-chip CMOS MSK coherent demodulator > >Suzuki, H.; Yamao, Y.; Kikuchi, H. > >Electronics Letters > >Volume 18, Issue 13, June 24 1982 Page(s):581 - 582 > >Digital Object Identifier 10.1049/el:19820393 > > >The Costas loop for MSK is modified to include a third term in the > >multiplier which is a half bit rate clock. The clock and carrier > >recovery are coupled together. > > >John > > Hi John, > > Thanks for the information. I will try to find and read it. By the way, > is it a reliable technique for GMSK demodulation? I want a technique which > is able to practically work.
I don't think it is a popular approach for GMSK. You might consider a simple limiter-discriminator solution, depending on your BT that can work. John
>On May 13, 4:11 am, "richard_zhang" <hardhear...@yahoo.com.cn> wrote: >> >On May 12, 11:40 am, "richard_zhang" <hardhear...@yahoo.com.cn>
wrote:
>> >> Dear all, >> >> >> I saw in google that costas loop can be used as the carrier
recovery
>> >> mechanism for coherent GMSK signal demodulation, but I did not find >> any >> >> detailed article about it. Can anybody give a good reference to >> implement >> >> costas loop for gmsk? >> >> >> Any useful weblink or technical article will be appreciated. >> >> >> Richard >> >> >There are some IEEE papers on this, here's one: >> >> >Single-chip CMOS MSK coherent demodulator >> >Suzuki, H.; Yamao, Y.; Kikuchi, H. >> >Electronics Letters >> >Volume 18, Issue 13, June 24 1982 Page(s):581 - 582 >> >Digital Object Identifier 10.1049/el:19820393 >> >> >The Costas loop for MSK is modified to include a third term in the >> >multiplier which is a half bit rate clock. The clock and carrier >> >recovery are coupled together. >> >> >John >> >> Hi John, >> >> Thanks for the information. I will try to find and read it. By the
way,
>> is it a reliable technique for GMSK demodulation? I want a technique
which
>> is able to practically work. > >I don't think it is a popular approach for GMSK. You might consider a >simple limiter-discriminator solution, depending on your BT that can >work. > >John >
John, More specifically, I want to implement a coherent gmsk demodulation for GSM, where BT = 0.3. Can you recommend some references on demodulation, carrier recovery and timing recovery. thank you.
On May 13, 9:41&#2013266080;pm, "richard_zhang" <hardhear...@yahoo.com.cn> wrote:
> >On May 13, 4:11 am, "richard_zhang" <hardhear...@yahoo.com.cn> wrote: > >> >On May 12, 11:40 am, "richard_zhang" <hardhear...@yahoo.com.cn> > wrote: > >> >> Dear all, > > >> >> I saw in google that costas loop can be used as the carrier > recovery > >> >> mechanism for coherent GMSK signal demodulation, but I did not find > >> any > >> >> detailed article about it. Can anybody give a good reference to > >> implement > >> >> costas loop for gmsk? > > >> >> Any useful weblink or technical article will be appreciated. > > >> >> Richard > > >> >There are some IEEE papers on this, here's one: > > >> >Single-chip CMOS MSK coherent demodulator > >> >Suzuki, H.; Yamao, Y.; Kikuchi, H. > >> >Electronics Letters > >> >Volume 18, Issue 13, June 24 1982 Page(s):581 - 582 > >> >Digital Object Identifier &#2013266080; 10.1049/el:19820393 > > >> >The Costas loop for MSK is modified to include a third term in the > >> >multiplier which is a half bit rate clock. The clock and carrier > >> >recovery are coupled together. > > >> >John > > >> Hi John, > > >> Thanks for the information. I will try to find and read it. &#2013266080;By the > way, > >> is it a reliable technique for GMSK demodulation? I want a technique > which > >> is able to practically work. > > >I don't think it is a popular approach for GMSK. You might consider a > >simple limiter-discriminator solution, depending on your BT that can > >work. > > >John > > John, > > More specifically, I want to implement a coherent gmsk demodulation for > GSM, where BT = 0.3. Can you recommend some references on demodulation, > carrier recovery and timing recovery. > > thank you.- Hide quoted text - > > - Show quoted text -
GSM signals provide training sequences to help the demodulator estimate frequency, timing, and phase. They are described in this book, as well as various web sites you can find using google: "GSM System Engineering", A. Mehrotra, Artech House 1997