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dtmf decoder with microphone

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togarha

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Hi!

My question is how to connect a microphone to the dtmf decoder mt8870.

I know the mt8870, but how I must polarize and connect a microphone to connect to the recommended mt8870 circuit...

Thanks in advance...

Regards,
 

togarha

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The datasheet say nothing about an microphone input, it's an general audio input, but not a specific microphone, but I connected a microphone between the general input and ground and the circuit does nothing. Then I suppose that I need to "polarize" the microphone to supply any kind of power to ensure that it can modify a signal and not generate it...

Thanks in advance...

Regards,
 

alzomor

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Hi

I think you need to study different the microphone types.
I think there's some types of microphone and the interface circuit change according to the mic type.
Microphone may be coil or capacitor based

you may google for microphone types

Salam
Hossam Alzomor
 

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