an incorrectly configured ESC telemetry source can lead to a notch
running at very low frequencies. A simple example is a lua script like
this:
function update()
esc_telem:update_rpm(12, 0, 0)
return update, 10
end
return update()
where motor 12 is unused.
with that script in place we get a 1.0078 Hz filter which leads to
massive phase lag and a crashed aircraft
this is a safety protection. We should also try to find out why the
INS_HNTCH_FREQ lower limit is not working
when we reset a notch we need to init the stored values to the current
value, rather than assuming that zero is the right value
this matters when switching IMUs in flight when we are only running
notch filters on the active gyro
This formulation of the notch equations lets the user specify the depth of the Notch. The presence of a diveide by A prevents the gain going to zero and therefore achieving a perfect notch. It also provides the risk that a user may attempt to do this and cause a divide by zero error. This change adds the ability to achive a perfect notch and removes the possibility of a divide by zero.
Add Notch Filter parameter checking
This delegates updates to a bank of NotchFilters located at an rpm frequency and harmonics. Center frequency can be updated dynamically. Notch parameters are configurable, including the number of harmonics to filter on. Updates to the filter parameters are optimized across the notch bank. Convert notch bandwidth and frequency to floats.
allow all filter harmonics to be controlled.
add destructor to harmonic notch.
don't allocate sub-filters for harmonic notch if no harmonics set.
