Help me with setting a microphone network

Microphone Network

Hi guys,

I would like to implement a number of microphone terminal which would share the same amplifier box. Only one microphone can be allowed to operate at a time through a switch or something like that. I'm not sure what signal form to be transmitted through the cable (CAT5 most probably) from the microphone to the amplifier. I'm aware that if I were to create a differential signal from the microphone input signal, only noise can eliminated but other contamination such as frequency shift cannot be avoided. Furthermore, the length of cable can be as far 50 feet which would results in great amount of lost.

One more thing, is there any CMOS IC that takes in analog signal and works as decoder at the amplifier end in order to allow certain microphone terminal.

Thank you very much.

Re: Microphone Network

I remembered I saw something in website of National Semiconductor.

Microphone Network

I recommend putting preamps close to the microphones. The unamplified output of a microphone is very low and can easily pick up noise when sent through long cables.

There are plenty of analog switch IC's such as analog devices SSM2402, I'm not sure if they are CMOS.