Existence of a voice level doppler shift in a supposedly digital scheme like
GSM is hard to accept...

> -----Original Message-----
> From: tcwug-list-admin at tcwug.org [mailto:tcwug-list-admin at tcwug.org]On
> Behalf Of Austad, Jay

> ...    GSM 1800/1900 has
> special provisions for handling frequency shifts due to the
> doppler effect,
> since many people talk on their phones while driving. ...

Maybe I'm missing a big piece of the picture (and the specs), but this
doesn't make sense.  GSM supposedly digitizes the voice at the handset, then
sends and receives digital packets.  The modulation for the digital encoding
would see doppler, but the voice digitizing and recovery in the handset
would not.  The modulation only does ones and zeros and probably with some
compressed error correcting code, so the modulation (subcarrier) doppler is
irrelevant for bit recovery.  "Channelizing" or some such might be affected
by the RF carrier frequency having a doppler shift, but PLLs probably
nullify that up to some speed such as you suggested.  Just what GSM doppler
are you discussing?

Just curious..