??? Audio Expansion Circuit ???

[xtp]

Does anyone have a schematic for an audio expander that is not very complicated?
I found one once but it had more than 100 components...
Note: The Audio Expander is the opposite of the Audio Compressor.

 

[audioguru2]

Hi Xtp,
Many years ago I used compander IC's from Philips. Some are still available and they have a nice Compander Cookbook online.
NE570
NE571
NE572
and more. ;D

 

[Shahriar]

Dear Audioguru

Can U give an explanation about what are Compandors and what
do they do?

I downloaded the NE570 Datasheet but couldn't guess what it does...

ThanX in advance
Shahriar

 

[Alun]

A compandor is a compressor and expander in one Package.

A compressor is a non-linear amplifier that has a low gain at the higher parts of a signal and higher gain at low signal levels.

A compressor has a logarithmic response and an expander has an exponential response.

Hence an expander increases the dynamic range of a signal and a compreser reduces it.

 

[audioguru2]

The professional wireless microphone systems I worked with use companders. The transmitters compressed the signal to raise its low-level parts well above the noise level, and the receivers expanded it back to normal dynamic range without noise. ;D