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Minimize GSM buzz noise in mobile phones

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PierreMars
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re: Minimize GSM buzz noise in mobile phones
PierreMars   7/30/2009 8:31:01 AM
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The simplest solution is to use a very low ESR supercapacitor at the power input to the RF PA. For class 10 GPRS, the envelope of the RF pulse is 1.15ms. To supply 2A or more for 1.15ms with low voltage droop requires a supercap (10's of mF, ESR < 100mOhms). This will average the current seen from the source, reducing large currents that may cause EMI radiated into neighbouring equipment or speakers, and also reducing any voltage ripple seen by the audio amp in the phone. Due to the size and cost of the supercap, this solution is more viable if the supercap is used for other purposes as well, such as LED Flash and improving audio quality.

MarcoPio
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re: Minimize GSM buzz noise in mobile phones
MarcoPio   7/29/2009 8:49:53 PM
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QWERTYASDF : probably the best solution is to use a module with digital audio input like new telit modules

NickPDA
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re: Minimize GSM buzz noise in mobile phones
NickPDA   7/29/2009 9:48:05 AM
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In my experience, the buzz is mainly caused in external (audio-related) equipment, the mechanism being rectification of the bursts by anything diodic. Fixing the vias in the handset or adding more capacitors to it is quite irrelevant to that!

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