Re: 80dB now but still needs improvement at 1KHz

On 7/11/2024 10:20 am, john larkin wrote:

On Wed, 6 Nov 2024 22:15:38 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
 

john larkin <jl@glen--canyon.com> wrote:
>
[...]

It's interesting that the classic filters (Butterworth, Chebychev,
Cauer) are based on mathematical approximations that pre-date
electronics. They were used to compose tables for artillery or
something.

>
Chebychef did his calculations on the mechancal lnkages used to operate
the valves of steam locomotives, generating linear motion and sharp
movement from the superimposed effects of rotary motions.

 I think the general idea is that if you truncate a power series, here
is a better set of coefficients than just chopping off the infinite
set.
 That mattered when math tables were computed by hand. Nowadays, a
computer can just use the first 150 terms.

That's a Russian (brute force) solution. Hamming windows are computationally cheaper.
--
Bill Sloman, Sydney