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Design >> Analog Design >> What caused the overshoot?
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Message started by ywguo on Mar 8^th, 2013, 6:32am

Title: What caused the overshoot?
Post by ywguo on Mar 8^th, 2013, 6:32am

Hi Guys,

I have an analog high pass filter, which has big overshoot. The following is loop gain/phase, step response, and close loop response. I could not figure out the reason of overshoot in the step response from the loop gain/phase and close response. Any comments are appreciated.

Title: Re: What caused the overshoot?
Post by ywguo on Mar 8^th, 2013, 6:34am

This is the step response with big overshoot.

Title: Re: What caused the overshoot?
Post by ywguo on Mar 8^th, 2013, 6:46am

This is the close loop gain and phase of the output node.

Title: Re: What caused the overshoot?
Post by Lex on Mar 8^th, 2013, 6:47am

My first guess would be zeros in your transfer function.

Title: Re: What caused the overshoot?
Post by raja.cedt on Mar 8^th, 2013, 7:09am

Hello Ywguo,
why it will be surprise to you, if there is no overshoot then you should surprise. High pass filter will contain zeor's at zero frequency. Please provide schematic.

Thanks,
Raj.

Title: Re: What caused the overshoot?
Post by RobG on Mar 9^th, 2013, 9:29pm

Look at a simple RC high pass filter and you will see that the step response is a spike just like what you are seeing

Title: Re: What caused the overshoot?
Post by threepwood on Mar 23^rd, 2013, 5:26am

Lex wrote on Mar 8^th, 2013, 6:47am:

My first guess would be zeros in your transfer function.

This is the first thing I thought about.

Or it could be charge injections during large-signal stimulation in transient.
Or, if it is a DAC, timing mismatchs between your digits (shifting from 0111 to 1000 for example)