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CPFSK synchronization.

Started by ajith shenoy August 25, 2013
Hello,

I am trying to demodulate a binary CPFSK with modulation index of 0.6
With correlation receiver & viterbi decoder I am able to demodulate a synchronized signal, but i am stuck with synchronization techniques.
Can anyone please let me know any ideas for synchronization.

Thanks & Regards,
Ajith
>Hello, > >I am trying to demodulate a binary CPFSK with modulation index of 0.6 >With correlation receiver & viterbi decoder I am able to demodulate a
synchronized signal, but i am stuck with synchronization techniques.
>Can anyone please let me know any ideas for synchronization. > >Thanks & Regards, >Ajith >
The phase of this signal will rotate + or - 0.6*pi radians every symbol time. You can exploit this to obtain an error signal for reference recovery. If modulation index is truely 0.6, then carrier phase and symbol timing are locked to each other and recoverying one is commensurate with recovering both. -Doug _____________________________ Posted through www.DSPRelated.com
On Monday, 26 August 2013 21:33:16 UTC+5:30, DougB  wrote:
> >Hello, > > > > > >I am trying to demodulate a binary CPFSK with modulation index of 0.6 > > >With correlation receiver & viterbi decoder I am able to demodulate a > > synchronized signal, but i am stuck with synchronization techniques. > > >Can anyone please let me know any ideas for synchronization. > > > > > >Thanks & Regards, > > >Ajith > > > > > > > The phase of this signal will rotate + or - 0.6*pi radians every symbol > > time. You can exploit this to obtain an error signal for reference > > recovery. If modulation index is truely 0.6, then carrier phase and symbol > > timing are locked to each other and recoverying one is commensurate with > > recovering both. > > -Doug > > > > _____________________________ > > Posted through www.DSPRelated.com
Hi Doug, Thank you for the reply. I have a system with 0.96us bit period & 312.5KHz frequency deviation. Hence modulation index is 0.6. I am not able to understand about error signal or carrier phase & symbol timing locked to each other. Can you please explain more. I am new to this synchronization. Thanks & Regards, Ajith
On Mon, 26 Aug 2013 09:34:30 -0700, ajith shenoy wrote:

> On Monday, 26 August 2013 21:33:16 UTC+5:30, DougB wrote: >> >Hello, >> >> >> > >> >I am trying to demodulate a binary CPFSK with modulation index of 0.6 >> >> >With correlation receiver & viterbi decoder I am able to demodulate a >> >> synchronized signal, but i am stuck with synchronization techniques. >> >> >Can anyone please let me know any ideas for synchronization. >> >> >> > >> >Thanks & Regards, >> >> >Ajith >> >> >> > >> >> >> The phase of this signal will rotate + or - 0.6*pi radians every symbol >> >> time. You can exploit this to obtain an error signal for reference >> >> recovery. If modulation index is truely 0.6, then carrier phase and >> symbol >> >> timing are locked to each other and recoverying one is commensurate >> with >> >> recovering both. >> >> -Doug >> >> >> >> _____________________________ >> >> Posted through www.DSPRelated.com > > Hi Doug, > > Thank you for the reply. I have a system with 0.96us bit period & > 312.5KHz frequency deviation. Hence modulation index is 0.6. > I am not able to understand about error signal or carrier phase & symbol > timing locked to each other. Can you please explain more. I am new to > this synchronization.
I think that Doug is mistaken in his statement. The _change_ in carrier phase may be locked to the symbol timing, but unless the carrier oscillator is locked to the symbol timing clock, the carrier will not be synchronized to the symbol timing. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com