Hi all, I was reading a book and came across this statement

“The frequency response of a digital filter takes place with respect to sampling rate at which the data passes through filter or is played back, in the case of offline processing. That is the digital filter creates the same interrelationships between output samples independent of sample rate; data passing through filter at one sample per second will be modified on a sample by sample basis in exactly the same way as a signal that passes through at one million samples per second. What will be different, however, is the playback rate means in terms of actual physical frequency response of the filter on data. “

Could someone please explain me what does it mean?

 

Simple: the frequency response of any given digital filter is purely function of the sample rate.

For example, a low-pass filter with a 100Hz 3db point at 1000 samples/second will have a 200Hz 3db point at 2000 samples/second.

 

The response of a digital filter is a f() of both sample rate and pole-zero
locations (filter coefficients used in algorithm).

https://www.slideshare.net/op205/basics-of-digital-filters-presentation


Regards, Dana.

 

Thanks All, this is so helpful.