Echo and Resonance Problem in Speaker Phone (Mobile Handset)


Hi,


I am facing some problem related to Speaker phone and microphone too.

" Make a call from or to Mobile Phone, switch the speaker ON,
During the call with the speaker you will find that there is a clear
ECHO coming with the sound from the other side, This appears clearly
when the volume of the speaker is the highest one; it even appears when
you decrease the speaker volume. Also you will hear a WHISTLE during
any speech coming out from the speaker. "

Can someone explain me the reason behind this?


Aloha,
Sumit

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