GSM uses Time division multiple access a.k.a TDMA with a 30kc wide signal.
The carrier freq it uses hops around with in a band near 1.9Ghz as CW
packet bursts.

Unshielded speaker components act as diodes, which in turn acts a AM
radio detector,
and turn your speaker into a receivers of the AM resulting signal.
That is the noise you hear.

I hope that helps.

-SN


DougSlug wrote:
"PowerHouse Communications" wrote in message
...

"DougSlug" wrote in message
...

In my office we often experience instances of a "galloping" sort of buzz
periodically coming from the PC speakers near co-workers who have
Cingular GSM cell phones. A preliminary Web search turns up many
instances of this problem. My understanding is that these phones
periodically communicate with the network, and during these brief bursts
the carrier is modulated at around 200 Hz resulting is a clear,
repeatable buzz pattern. How is this buzz getting into the PC speaker
amplifier, and, more importantly, how can it be prevented?

GSM is your problem. Find a cell company that doesn't use the GSM
standard, and you problems will go away; and just maybe the honey bees
will survive...

GSM is junk, and should have never seen the light-of-day. The wife's
phone uses GSM, and it interferes with EVERYTHING. Any speaker in the
house buzzes, doesn't matter what it's connected to, screws up the picture
on the TV, computer monitor, etc. Causes all kinds of interference to
nearly every radio in the house (communication or otherwise).



But why is this? I'd like to understand what GSM does that the other
systems don't do. Is a higher transmit power needed from the handset for
some reason? Guess I need to do some more background research.

- Doug