# Baseline Recovery time of Shaper Amplifier output

TL;DR Summary
I have a Bipolar shaper amplifier and I need to measure its Baseline Recovery time. Though I tried to study baseline recovery time concept but could not understand it.
From the picture in attachment (Black Curve) can some body kindly comment on what Baseline Recovery time is and how to measure it?

Welcome to the PF.

Can you post a link to the datasheet for your amp? With a quick Google search I find lots of helpful information on the baseline recovery time of pulse detection amps. Can you post links to some of the reading you have been doing, and ask specific questions about the parts you don't understand? Thanks.

There are different, somewhat common, definitions. They are all based on the time it takes from a step input (like the edge of a square wave) for the output to reach its final value.
They are:
[*] Time-Constant: when the output reaches to 37% of its final value
[*] 5 times the Time Constant: the output reaches to <1% of its final value
[*] 10%: the output reaches to <10% of its final value

For audio stuff, I expect that the 10% rule would be adequate but not ideal.

For a Rock Band you may get away with one Time Constant, 37%.

For Classical, or the 1812 Overture, consider 3 to 5 time constants. ( 3 Time constants gets you within 5% of final value. With the huge dynamic range you would want the recovery time to be quite fast to avoid audible distortion.)

Cheers,
Tom

p.s. These numbers are based on somewhat limited experience, so if someone else has different recommendations, believe them!

I take it this is for a detector readout application. Baseline recovery and restoration is covered in Knoll (the standard text for this area). Basically you have to define how close to the "final value" you need to get and measure that.
What Tom G. said is exactly right, but for you, a simpler way is to put a bunch of equal, widely spaced pulses in, find the final value (since its a bipolar shaper the final value should be the dc operating point), and then see when the output reaches 1% of that value (1% is typical for the accuracy of the kinds of detectors you would usually be reading out). Depending on what you're using the shaper for, it may be a different number.