Explanation about RATEEST interval and ewmalog

Hi

What is --rateest-interval and --rateest-ewmalog?

--rateest-interval amount{s|ms|us}
Rate measurement interval, in seconds, milliseconds or
microseconds.

--rateest-ewmalog value
Rate measurement averaging time constant.

I'm using interval 1.0s and ewmalog 2.0s but I don't understand how these parameters works together.

Any further explanation?