Still Going

[Rick Marken (930315.1515)]

Martin Taylor (930315 18:00) --

(Rick Marken 930315.0900)

understand that there IS NO INFORMATION
ABOUT THE DISTURBANCE IN THE STIMULUS in control tasks and you will
be able to make beutiful PCT music

I understand that when the gain is infinite and there is zero transport
lag around the loop, this is true.

Irrelevant. It is always true -- unless the control system is not
acting at all (zero gain) in which case there is complete information
about the disturbance at the input to the control system. Of course,
now none of this information shows up in the output since the output
is zero all the time.

I still hope to make beautiful, but less ethereal, PCT music.

Your hope will be achieved when you can say -- confidently and
with no reservations:

THERE IS NO INFORMATION ABOUT THE DISTURBANCE IN THE INPUT TO
A CONTROL SYSTEM.

Amen.

Rick