classification of offset 8-psk

Hello friends,

I would like to know if it would be correct if we classify the 3pi/8
offset 8-psk modulation scheme used for EDGE as a type of linear CPFSK?
I am quoting this statement based on the understanding that GMSK used for
GSM is a non-linear CPFSK.

Regards,
Pankaj

On Wed, 24 Jan 2007 12:11:19 -0600, "pankaj_029" <jigs52@hotmail.com>
wrote:

>Hello friends,
>
>I would like to know if it would be correct if we classify the 3pi/8
>offset 8-psk modulation scheme used for EDGE as a type of linear CPFSK?
>I am quoting this statement based on the understanding that GMSK used for
>GSM is a non-linear CPFSK.

I think I'd say no to that one.

8-PSK is PSK, not FSK, and the offset is just to keep the symbol
transitions out of the center of the I-Q plane (i.e., to keep the
instantaneous output power from going to zero).  That small change
doesn't make it FSK.



Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org

"pankaj_029" <jigs52@hotmail.com> writes:

> Hello friends,
>
> I would like to know if it would be correct if we classify the 3pi/8
> offset 8-psk modulation scheme used for EDGE as a type of linear CPFSK?
> I am quoting this statement based on the understanding that GMSK used for
> GSM is a non-linear CPFSK.

I would say yes, it is a linear modulation. It can be viewed as
16-PSK, which is linear. 
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