No way to design a filter which Fpass = Fs/2

[rgetz]

Michael pointed out:

If you want a filter which is basically flat, with no attenuation anywhere (just to enable the decimation), this isn't possible.

Setting datarate to 10, fpass and fstop to 5, FIR to x4 : Design filter just returns nothing.

I think this was the "equalize" option (that isn't implemented yet).
-Robin

[tfcollins]

The way we configure the Parks-Mcloughlin algorithm currently is basically fighting this design strategy. I can change things and basically enable this passband mode if that’s we want

[rgetz]

I expected as much - I think that is why I thought it was just better to have an "equalize" option.

I would assume that if we want a flat response, the user would not select "low pass". ;)