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TI71M01D06-01EN 3rd Edition: 2012.12.01
(2) Types and Characteristics of Filters
The three types of filters listed in the table below are provided for resonance
countermeasures. Use them for their respective best purposes according to the
characteristics of the resonance.
Characteristics of Various Filters
Application Precaution
Phase lag
compensation filter
This is a first-order delay filter. Since it can adjust the
bandwidth frequency and amount of damping, it can
suppress the amount of phase shift better than the
velocity feedback filter.
Oscillation caused by phase shift
tends to occur if the velocity control
bandwidth and the frequency setting
of the first-order compensator filter
are close to one another.
Notch filter
This filter can significantly dampen the gain at any
frequency. Use this filter when there is resonance with
a high peak gain in a narrow frequency band.
Resonance remains in case the
resonance gain is high in a wide
frequency band.
Velocity feedback
filter
This is a first-order delay filter that allows lowering the
gain at high frequencies dramatically. Use this filter
when there are several resonance points among the
high frequencies.
Since the phase shifts up to 90
degrees when this filter is used,
phase shift oscillation tends to
occur.