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How many Noncoherent demodulation methods for CPM are there ?

Started by isgone January 7, 2008
and what are the methods? thanks !just tell me some of them,i need to know
some Noncoherent demodulation methods for CPM. your help is appreciated !
On Jan 7, 10:09 pm, "isgone" <isg...@hotmail.com> wrote:
> and what are the methods? thanks !just tell me some of them,i need to know > some Noncoherent demodulation methods for CPM. your help is appreciated !
I won't fill out your list, but I'll mention a couple of interesting ones -- average matched filter and sequence detector. John

isgone wrote:
> and what are the methods? thanks !just tell me some of them,i need to know > some Noncoherent demodulation methods for CPM. your help is appreciated !
There are only two approaches: coherent (where Fi is used) and incoherent (where dFi/dt is used). There is an infinite number of the equivalent ways for the implementation of each approach. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
On Jan 8, 9:49 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com>
wrote:
> isgone wrote: > > and what are the methods? thanks !just tell me some of them,i need to know > > some Noncoherent demodulation methods for CPM. your help is appreciated ! > > There are only two approaches: coherent (where Fi is used) and > incoherent (where dFi/dt is used). There is an infinite number of the > equivalent ways for the implementation of each approach. > > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
There is a bible on CPM: http://www.amazon.com/Digital-Modulation-Applications-Communications-Theory/dp/030642195X In it you will see that there is a class of techniques that involve filtering the arbitrary phase baseband CPM data with a set of complex kernels that represent phase transitions corresponding to bit sequences. The decision circuit can choose the filter producing the largest magnitude response to decide what sequence was transmitted. This is sometimes called sequence processing. Its performance can approach coherent as the sequence length gets long, provided that the parameters are not off too much. It's worth a look. John
John <sampson164@gmail.com> writes:

> There is a bible on CPM: > >
http://www.amazon.com/Digital-Modulation-Applications-Communications-Theory/dp/030642195X For $204 it better damn well be gold-plated as well. -- % Randy Yates % "Midnight, on the water... %% Fuquay-Varina, NC % I saw... the ocean's daughter." %%% 919-577-9882 % 'Can't Get It Out Of My Head' %%%% <yates@ieee.org> % *El Dorado*, Electric Light Orchestra http://www.digitalsignallabs.com


> On Jan 8, 9:49 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> > wrote: > >>There are only two approaches: coherent (where Fi is used) and >>incoherent (where dFi/dt is used). There is an infinite number of the >>equivalent ways for the implementation of each approach.
> There is a bible on CPM: > http://www.amazon.com/Digital-Modulation-Applications-Communications-Theory/dp/030642195X > > In it you will see that there is a class of techniques that involve > filtering the arbitrary phase baseband CPM data with a set of complex > kernels that represent phase transitions corresponding to bit > sequences. The decision circuit can choose the filter producing the > largest magnitude response to decide what sequence was transmitted. > This is sometimes called sequence processing. Its performance can > approach coherent as the sequence length gets long, provided that the > parameters are not off too much. It's worth a look.
Too many words to describe the simple thing: one can get an estimate of phase by observing a window of N symbols. As N goes to the infinity, this becomes equivalent to the coherent demodulation. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
On Jan 8, 6:28&#2013266080;pm, Vladimir Vassilevsky <antispam_bo...@hotmail.com>
wrote:
> > On Jan 8, 9:49 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> > > wrote: > > >>There are only two approaches: coherent (where Fi is used) and > >>incoherent (where dFi/dt is used). There is an infinite number of the > >>equivalent ways for the implementation of each approach. > > There is a bible on CPM: > >http://www.amazon.com/Digital-Modulation-Applications-Communications-... > > > In it you will see that there is a class of techniques that involve > > filtering the arbitrary phase baseband CPM data with a set of complex > > kernels that represent phase transitions corresponding to bit > > sequences. The decision circuit can choose the filter producing the > > largest magnitude response to decide what sequence was transmitted. > > This is sometimes called sequence processing. Its performance can > > approach coherent as the sequence length gets long, provided that the > > parameters are not off too much. It's worth a look. > > Too many words to describe the simple thing: one can get an estimate of > phase by observing a window of N symbols. As N goes to the infinity, > this becomes equivalent to the coherent demodulation. > > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultanthttp://www.abvolt.com- Hide quoted text - > > - Show quoted text -
The phase is actually discarded in the decision circuit. It operates on magnitude only. John