Re: "all pass" thought about (analogue) compression

From: John Woodgate (jmw_at_jmwa.demon.contraspam.yuk)
Date: 01/07/05 

Date: Fri, 7 Jan 2005 08:08:52 +0000

I read in sci.electronics.design that Ken Smith
<kensmith@green.rahul.net> wrote (in <crktu7$gpl$1@blue.rahul.net>)
about '"all pass" thought about (analogue) compression', on Fri, 7 Jan
2005:

>Since the band of interest is 300Hz to 3KHz,

It isn't: I've posted that it's 100 Hz to 5 kHz (at least).

>we don't have to worry
>about the harmonics of the frequencies above 1KHz. Those can be removed
>with a simple low pass filter. I haven't verified it yet but it seems
>to me that 3 stages of phase shifter and 4 clippers should be able to
>make a significant compression of amplitude but make less that 5%
>distortion on a sine wave.

Interesting, a bit more ambitious circuit-wise than I really expected,
and how to realise the weird fractional power law?
>
>The intermodulation distortion will not be made zero by this method. If
>the input has more than one frequency component, the distortion will be
>much higher.

The input is mainly speech, but there could be music as well. In any
case, many frequencies. 

-- 
Regards, John Woodgate, OOO - Own Opinions Only. 
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

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