This is an advert of sorts but I don't pofit from it.

Read this if you are interested in being able to produce active filter
designs in under 5 minutes.

Years ago I purchased a book "Rapid Practical Designs of Active Filters".

It allows you to design all the standard hi/lo/band/all pass filters in 2 to
8 or so poles in Butterworth/Chebyshev/Bessel/Dogsbreakfast :-)
configurations in about 5 minutes using just a 4 function calculator , once
you have got the hang of the book. It also gives lots of useful comments on
why to use various designs. A brilliant book. My copy was stolen long ago.

Nowadays computer programs and integrated filter chipos and swutched
capacitor filters etc have to a fair extent redundified such books. They
still have their place. Using a 2 pole VCVS unity gain design you can design
a 2 or 3 pole low pass filter using a single transistor in emitrter follower
mode. Sure, if you know what you are doing you can do this from 1st
principals but this book shows you how easily and rapidly. 5 poles = 2
transistors etc.

I have just purchased a 2nd hand copy from USA via ABE books network. Very
happy with it.
I didn;t realise that a 2nd seller who I queried was holding a copy for me.
It costs $15US plus postage.
They are on Oregon.

If anyone is interested email me privately and I'll copy you their reply and
address etc.
If I get many replies I'll just reply to the first few.

I cant recommend ABE search site too highly for 2nd hand books.

    www.abebooks.com


RM