Buzzing on GSM audio
rivalarrival at neo.rr.com
Sat Jul 26 03:30:20 CEST 2008
Jim Morris wrote:
> Dave Clark wrote:
>> Can you correlate the buzzing to your signal level? IIRC, most phones
>> will increase transmit power as needed to overcome noise. If the noise
>> is caused by RFI from the GSM radio, increased power would tend to
>> increase the interference.
> I have a very low signal here one bar at most, I haven't tried it where there is good reception, as
> I can't really use it as a phone yet. However with that clue I'll try it ASAP in an area where I get
> better reception.
> FWIW my other Cell phones also get very low reception here, but don't have any noise.
> I hope if this is a H/W problem we can get it fixed even after the warranty expires as it definitely
> makes the phone a brick otherwise.
I know GSM transmissions can present significant interference on audio
equipment - if my phone (any GSM phone) is on my desk, I can hear
periodic static in my computer speakers as the phone "checks in" with
the cell tower - it sounds like three quick, buzzes in about 1 second.
This happens a couple times an hour.
When it receives a call, I get a steady buzz starting 1 to 3 seconds
before the phone rings, and continuing until I hang up.
I would imagine that ALL cell phone hardware would have to deal with
this audio interference, and since I don't hear it in many other phones,
I'm pretty sure it can be filtered out with some sort of audio processing.
Incidentally, the speaker-phone feed back could probably be resolved
with the same filter.
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