Reply by John ●May 14, 20082008-05-14
On May 13, 9:41&#4294967295;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 &#4294967295; 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. &#4294967295;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
Reply by richard_zhang ●May 13, 20082008-05-13
>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.
Reply by John ●May 13, 20082008-05-13
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
Reply by richard_zhang ●May 13, 20082008-05-13
>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.
Reply by John ●May 12, 20082008-05-12
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
Reply by richard_zhang ●May 12, 20082008-05-12
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