Document Type
Thesis
Date of Award
1-31-1990
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical and Computer Engineering
First Advisor
Joseph Frank
Second Advisor
Stanley S. Reisman
Third Advisor
Sol Rosenstark
Abstract
The adaptive FIR digital filter is designed to suppress the noise in the tape recording and audio communication systems. The cutoff frequency of the digital FIR filters can be varied adaptively depending on the energy level of the input signal. In audio communication, especially, in tape recording systems, the noise obviously gets much bigger, when the frequency band of the system increases. The noise reduction system makes use of a phenomenon called masking, where the big signal-to-noise ratio makes human ears not sensitive to the noise. In a constant interval time, the system detects the signal level and compares the signal level with a set of threshold values, then, selects one of the digital FIR filters in order to make the signal-to-noise ratio large. If the signal level is less than about -30dB or -40dB, the system attenuates this extremely weak signal, because this signal level is very close to the noise level, and it is felt that it is preferable to hear a pause rather than noise.
We design the FIR digital filters and simulate the FIR digital filters. In the appendix, we implement the adaptive FIR digital filters with TMS320C25 DSP microprocessor software assembler language and hardware design.
Recommended Citation
Pang, Jack Jiabing, "Adaptive FIR digital filter design and simulation in the noise reduction system" (1990). Theses. 2886.
https://digitalcommons.njit.edu/theses/2886
