🚀 go-pugleaf

In article <se0biINNaaa@network.ucsd.edu> Matt Kennel writes:

> I don't understand.  How is having a 'poor slew rate' any difference from
> high-frequency dropoff in response?  Intuitively, they seem to be
> two ways of describing the same thing, though "poor slew rate" provides
> a bit more physical intuition.


It's intuition that kills this group and makes it so frustrating to read!

What you are asking cannot be simply answered.  A short answer is that the ability of a system to follow a an input is a function of both frequency AND amplitude.  Differentiate cos(wt) or graph two superimposed sinusoids of same frequency and different amplitudes and look at the slopes at zero crossings.

For an in-depth treatment, you will need to consult a basic text on control systems where order (type) and errors are discussed.  One designs and stabilizes control systems by the type of driving functions expected, but a good characterization can be made by analyzing response to three command
types: a step change in position, a step change in velocity (ramp) and a step
change in acceleration (parabolic function).

For systems of order 3 or higher, there will be no steady-state position, velocity, or acceleration error.  For a second-order system, which is typical of most feedback-stabilized amplifiers, there will be a finite but constant
acceleration error, meaning that the output will follow the input with a constant position error (lag). 
 
 

Rich


Good taste is timeless.
Why is a good time often tasteless?