? <cs_posting@hotmail.com> ?????? ??? ??????
news:1172031439.228710.31640@l53g2000cwa.googlegro ups.com...
> On Feb 20, 7:21 pm, Mozzy <d...@account.com> wrote:
>
> > On the other hand, you can get a cheap electret microphone designed to
> > be worn in the ear (as a phone-recording microphone) which is remarkably
> > resistent to cellphone RF.
>
> Generally the way intereference gets in is by speaker or power or
> signal wires acting as antennas. If a wire doesn't need to carry a
> high speed signal, you can bypass it with an RF choke in series and/or
> capacitors to ground. And put the circuit in a shielded enclosure.
> Chokes, and perhaps coaxial microphone cable, should help quite a bit.
>
> With GSM phones, the worst interference seems to be when the network
> is getting ready to ring them. In fact, I can often tell when my
> phone is about to ring because of what happens to my computer
> speakers, or car radio.
Err...I hope that it doesn't do something similar to our brains?(Just now
reading Stephen King's cell).I have measured the electrostatic field of my
Nokia 1100, and is 11 V/m at, maybe, 1/2", when calling (when idle,
something like 0.44 V/m)




> Chances are the phone won't be heard in its
> own headphone because it probably has it's audio jack bypassed with
> chokes and its amplifier not only well shielded, but also muted at
> this point. And nobody is yet on the other end to hear if the
> microphone is being interfered with. Presumably a phone that does
> voice recognition could even know exactly when it is transmitting its
> stronger pulsed signals, and thus if necesssary not listen right then,
> to avoid confusing itself.
>



--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
dimtzort AT otenet DOT gr