How to connect audio line into mic?

[umery2k75]

audio into mic




Hi,

Actually I don't want to use the MIC, I have pre-recorded message in the voice IC and I want recorded signal to go as the MIC signal in the device.I don't know if I can make the direct connection, I'm afraid for damaging the device, by the output of the VOICE IC.So do I have to go for some indirect connection, that is do I have to put the de-amplifier in it of some sort, or should I use some passive circuit, to reduce the voice voltage/current, so that it meets the MIC input characteristics.Well, I know that amplifiers are needed when original signal is to be needed in an amplified version, but I think in this case, I might need some de-amplifier that will produce the de-amplified version of the original signal, so that I don't exceed the maximum voltage as given me in MIC input characterisitc.I also have taken the waveform of the audio signal coming from the VOICE IC(that were going to speakers), I had set the probe to X10.In the waveform the speaker was connected with the VOICE IC.




PLease tell me, as what kind of pointers should I take into consideration and in which way I can accomplish this.

Thanks

 

[manish12]

why you not use pc recorder to record from chip , it is quit well ! and reliable

 

[umery2k75]

No, I want to use both VOICE IC and the MIC device.

 

[FvM]

Hello,

I think, mic input pin mapping can be different, at least I saw mono mic input at tip with supply voltage at ring, and stereo input, both inputs with superimposed supply.

Basically you need an attenuator to reduce line input to mic level, this is simply a resistive divider for each channel to avaid mic preamplifier overload.

Regards,
Frank

 

[PRAVEEN K]

Hi,
One simple solution you can try..... Just connect a 1uF capacitor in series to speaker mic connection. This will isolate the DC level and impedence of speaker and mic.

 

[umery2k75]

Thanks for the reply. This project was more than 2 year old. I don't remember what I did,but it had worked.

Added after 1 minutes:

This will isolate the DC level and impedence of speaker and mic.

I don't think you can isolate the impedance of speaker & mic, they must be match.Isolation means a complete mismatch or like a open connection, in your case.