Improved Transient Frequency Response of IIR Filters with Multiple Frequency Initialization

Abstract

This paper presents a new design method for IIR notch filters with improved performance while operating with a limited number of samples. The design criterion is to minimize the error between the steady state and transient frequency responses while utilizing the initialization technique. The new filters which use multiple frequency initialization offer better transient frequency responses than conventional steady state filters with initialization.

Second-order TDTL with initialization process

“…Initialization and loading the internal memories with steady-state value other than zero is used to improve the transient performance of digital filters [6] as stated earlier. Therefore, the improvement of the loop filter response has an effect on improving the overall performance of the loop in term of acquisition time to reach the required steady state.…”

“…This obviously compromises its performance, particularly for applications that require fast response. One way of improving the transient response of a digital filter is by initializing its internal memory with a value other than zero [6]. This requires fast initialization process of the loop filter memory to calculate the steady state value from the incoming input signal.…”