-=> Quoting Rob Sargeant to The Real Tom Marks <=-
 RS> Here in the Charlotte area (BellSouth Mobility DCS), the signal
 RS> strength does not have to be all that poor to experience garble (that
 RS> "kinda funny" sound you mentioned), which seems to me to be a
 RS> degradation of the sampling rate used in the A/D conversion process,
 RS> from what my previous experiences with A/D conversion and digital
 RS> encryption tell me.
Since I have a CDMA phone, and my GF has a GSM/TDMA phone I get to compare
them quite often.  With my phone I can have 0 signal strength, as long as
no service is lit up and my phone will operate fine unless it is on the
verge of getting dropped.  The GSM/TDMA phone on the other hand gets garbled
even when there is a bit of signal strength on there, although most of the
time the signal strength meter is usually full.
 RS> Ours is a GSM system... I would guess that they are using PCM for the
 RS> A/D conversion, but I wonder what the sampling rate is? As good as it
 RS> sounds, I'd have to guesstimate a rate of around 45-50Kbits/sec. or
 RS> better. For it to degrade to the point it does (before it drops your
 RS> call), I estimate that the sampling rate drops to 4800 or lower.
The CDMA phone I'm using has vocoders that operate at 13000 or 8000 depending
on what the cell system has it set up for, I believe mine is set at 13000
and there is one in LA that is set at 8000 but they said the sound quality
is reall the shits on that phone system.
 RS> As could be expected at 1900 Mhz, range isn't much better than
 RS> line-of-sight to a cell site. I have two cell sites about 1/2 mile on
 RS> either side of me, and the signal strength, even outside, leaves a lot
 RS> to be desired - at this time.
That is strange.  I don't know where one pacific bell cell site is, and since
I live in a residential area, I would be able to tell if they put up anything
even a small broadcaster.
 RS> What gets me is that they boast seamless coverage along the
 RS> interstates and in my general area, yet I experience a LOT of dropped
 RS> calls as opposed to being handed off to another site. And, as your post
 RS> mentioned, echo suppression seems to be a BIG problem.
I've gotten dropped only once or twice with the GSM/TDMA phone but a couple
of times with the CDMA phone.
... Words, words, words.  And no place to put them all!
~~~ ReneWave v2.00+
--- Renegade
---------------