HopeRF feedback

JDH services jaydeeaich at gmail.com
Sat Jun 26 17:43:22 EDT 2010


On 6/25/10, Werner Almesberger <werner at openmoko.org> wrote:
> JDH services wrote:
>> isn't the hard part of gmsk the demodulation?
>
> I don't know enough about signal processing to tell with certainty,
> but I would think so, too. Of course, if Silab's examples set up
> the transmitter such that it generates a signal with all the
> properties of MSK we could find, and Silab's examples aren't just
> a hoax, then they must also have solved the demodulation.

THat's all find for the world where you live in but for the rest of us
Silabs don't use MSK

see:
http://www.silabs.com/pages/DownloadDoc.aspx?FILEURL=Support%20Documents/TechnicalDocs/Si4430-31-32.pdf&src=SupportDocLibrary

It clearly says at he bottom of the ModIndex 1.0.  MSK has a MonIndex
of 0.5 in the real world.

and from one of the other papers your mentioned.

"The GMSK VCO-modulator architecture as shown in the first is simple but is not
however, suitable for coherent demodulation due to component tolerance problems.
This method requires that the frequency deviation factor of the VCO
exactly equals
0.5, but the modulation index of conventional VCO based transmitters
drifts over time
and temperature."

Sincerely,
Panthera Tigris Altaica




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