REDUCTION APPROACH OF TRANSIENT PROCESS OVERSHOOT IN CONTROLLED TUNABLE LOW PASS DIGITAL FILTER

Abstract

Digital signal processing is widely used in modern technology, including robotics, medical
technology, etc. Thus, the controlled digital filters are used to eliminate the constant component of
the output signal at the output of an analog-to-digital converter. This also reduces the low-frequency
interference level spread out on the frequency axis to the left of the lower boundary of the signal
spectrum. In actual situations, signals are subjected to a variety of disruptions and noises; however,
applying a filter may suppress these noises and produce a clean signal. Controllability means the
explicit dependence of the filter coefficients on the cutoff frequency. A transient occurrence can arise
in a digital filter, which is indicated in the overshoot of the signal. A change in the cutoff frequency
during filtering operation could cause this transient event. In this report, a Butterworth LPF filter is
used to offer a compensation strategy for reducing this overshoot. A transient is an overshoot (drive)
in the result timing chart. This drive is an after effect of the adjustment of the coefficients (boundaries)
of the filter during filtering (this is classified "on-the-fly tuning"). By using the MATLAB program,
the transient process resulting from the restructuring of the filter was investigated and the
formulas were checked compensation of this transient process. It was found that the application of
such compensation reduced the negative effects of the transition process. This decrease depends on
the order of the filter, the adjustment coefficient (the ratio of cut frequencies before and after adjustment)
and the moment of adjustment (for the periodic signal).