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

On Thu, 07 Nov 2024 13:23:27 +0100, albert@spenarnc.xs4all.nl wrote:

In article <n5unijlr25iffo7v22eb3rhg5pcnrk87nv@4ax.com>,
john larkin  <jl@glen--canyon.com> 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.

>
They can, but don't do that. Wasting computer time for using a
lot of terms is just wasteful. Minimax polynomials and the likes
(rational approximations) are used all over the place, thanks
Tsjebisjof.

>

>
Groetjes Albert

Calculating a sine or a log to 15 significant digits wastes
milliwatts. AI wastes gigawatts.