http://zorro-trader.com/manual/en/tutorial_fisher.htm

Regarding The tutorial refers to 30 as the cutoff period. I'm trying get more understanding of this. Ehler's HTDcPeriod does not have this arg. The Transformation filters manual http://zorro-trader.com/manual/en/filter.htm just calls the second arg "period". The description doesn't say what it's for. I do notice the phrase "valid range = 10..60 bars." but I'm not sure if that is meant to be the range of the input or the output.

Without clarity in the manual, I started experimenting and trying to infer the sense of this parameter. I observed that the value of DominantPeriod(Price, P) can be less than P. See EURUSD, 60m. DominantPeriod(Price, 60) has range (16.5, 60.4). DominantPeriod(Price, 10) has range (10.8, 46.7). I enter the realm of wild guessing at this point.

What is the sense of the second argument? Can you please start at the beginning?

A few additional nits about the Workshop 5.

1. Further down it says

The variable Period is a single var, not a series.

2.

This is different from the script


3.

errrrm

same with "The LowPeriod variable, used for the HighPass filter time period, is multiplied with the return value of an optimize function" etc.

It is the cutoff period of a highpass filter that removes trend and normalizes the data before the dominant period is determined.

DominantPeriod is not used in Workshop 5 - the online version was not up to date. I've now uploaded the page from the manual.

I see . I'll study this new workshop instead.

please do not forget about the manual for DominantPeriod
http://zorro-trader.com/manual/en/filter.htm Especially where it says "valid range = 10..60 bars". Based on what you just said , I think that sentence refers to the output, not the input. That was not my first guess.