erik.vonreis@LIGO.ORG - posted 08:51, Tuesday 14 January 2025 - last comment - 11:03, Tuesday 14 January 2025(82263)
H1OMC0 models were updated
All h1omc0 models (h1iopomc0, h1omc, h1omcpi) were restarted with version 5.3.1 of the RCG. This version changes the ramp function when turning on and off ramp-switched filters from a linear ramp to the so-called quadratic ramp.
A linear ramp has the formula r = q where q = (t - t0)/(t1 - t0), the new ramp has the formula r = -q4 + 2q2, which has the nice property that dr/dq = 0 when q = 0 or q = 1.
This change is an attempt to address the problem described here: 81638
The ramp formula was taken from the ramp used to end excitations in awgtpman.
Some plots comparing the ramps, taken from simulation of a user model switching on a filter with gain.
All models on h1omc0 whose filter-modules uses ramp switching filters have the new spline ramps. The models and number of ramping filters are summarized in this table, details are in attached text file.