Re: The low distortion oscillator problem

On 2025-02-06 00:44, john larkin wrote:

On Thu, 06 Feb 2025 05:08:16 +0000, JM
<sunaecoNoChoppedPork@gmail.com> wrote:
 

On Thu, 6 Feb 2025 03:58:59 +1100, Bill Sloman <bill.sloman@ieee.org>
wrote:
>

There have been quite a few postings about 1kHz low distortion sine wave
oscillators.
>
The problem is that if you want a get stable output from a sine wave
oscillator you have to add a non-linear element to control the gain
around the oscillating circuit.
>

>
You don't.

 What limits the amplitude?
 

We had a long discussion of this in one of the myriad other 1-kHz oscillator threads.  One approach is to use a comparator+integrator to control the tail current source (suitably cascoded).
The key is for the gain-setting mechanism to be outside the oscillator loop, so that it doesn't get run through its range on each cycle.  The bias of the active device does change some, of course, but that's harder to avoid.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com