Why does Differentiator Filter produce significantly different results from the Derivative block when differentiating a signal?

I tried to compare the numerical results from Direct form FIR fullband differentiator filter - Simulink (mathworks.com) and Output time derivative of input - Simulink (mathworks.com) using the following setup:

And to my surprise, results from both blocks are significantly different from each other in magnitude:

How could this difference be logically and scientifically explained?

Answer 1

[Bhavana Ravirala]

Hi ,

The output of the filter will be depending on multiple factors like passband ripple, stopband ripple, and filter coefficients. Due to this, the output will be different. You can check this out by unchecking the box of Design minimum order filter and comparing both the cases, you can observe that the values are completely different.

In the case of the derivative block, the major functionality of the block is to differentiate, and it gives us the expected output.

Hope this helps!!