GSM is particularly  bad for RFI because it has a 216 Hz frame rep rate, 
which, when rectified, looks like a 216 Hz square wave. Old analog 
phones had a continuous carrier and CDMA phones have less of an EMC 
footprint as well.


Jack


Mike Hord wrote:
>>  I recently found that they are badly affected by the
>>  proximity of an operating GSM cellphone. Their display goes
>>  quietly mad running up and down and or sitting at random
>>  values. Remove phone from area and all is well again. Range
>>  of effect is up to about ?500 mm?.
>>     
>
> Perhaps it's because it's consumer electronics?
>
> When we release a new device, we test it to the spec that our
> customer demands.  It HAS to pass.  Consumers don't demand
> the same.
>
> OTOH, we don't test to the level of emissions from a cellphone
> at 500mm.
>
> Mike H.
>   
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