Re: Final final 1kHz oscillator

john larkin <JL@gct.com> wrote:

On Sun, 17 Nov 2024 02:01:25 +0000, JM
<sunaecoNoChoppedPork@gmail.com> wrote:
 

On Thu, 14 Nov 2024 11:14:28 -0500, "Edward Rawde"
<invalid@invalid.invalid> wrote:
 

<snnnniiiiiipppp>

Because of common mode (non)linearity.  In most op-amps (especially
older designs) the distortion generated by the common mode signal is
typically one to two orders of magnitude larger than the transfer
distortion.  If it is not clear from the data sheet, it is best to
measure the CM performance or just assume that it's 40dB worse than
the specified figure.

 
To quote Jim Williams, "always invert."
 

“Except when you can’t.”

Just the ESD diodes are a distortion hazard. I've seen people
bootstrap the power supplies to improve CMRR.
 
>

Pease has an article somewhere about how to measure CMR and PSR
correctly—as he says, most of the obvious methods actually measure
open-loop gain.

Cheers

Phil Hobbs



--
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics