How to filter out peaks in a signal in Simulink?

I want to filter out peaks in signals in Simulink without causing a delay in a signal. I have tried median filters but I need a large sliding window value (20+) to filter out peaks, doing so will introduce a large delay in the output signal which is undesirable. Is there another way to effectively filter out peaks without causing a significant delay in the output ?

Here is an example image of how a signal looks like.The peaks here are at 15s-16s mark.

Any help would be greatly appreciated. Thanks in advance!

Answer 1

[Naman Chaturvedi]

Hello Darshan,

You cannot filter the signal without some delay. You can choose the low pass filter appropriate for your purpose with some delay. It is not possible to perform a zero-phase filter in real-time because a zero-phase filter requires filter coefficients that are symmetric around zero. That means that the filter is non-causal, or that current output depends on future input. This of course is not possible in the real-time case (simulink) and can be faked as in the case of filtfilt in MATLAB during post-processing.

You can even post process the signal by Compensate for the Delay Introduced by an FIR Filter or passing the signal again through a conjugate of the filter used in the simulink in the first place.

[Darshan Reddy]

Hi Naman,

I can imagin it being difficult to do it in simulink since it is in real-time and in my case, the signals also needs to be filtered in real-time. So, I can't make use of any post processing methods too.

Anyway, thanks for the info.