Filter Banks for Spectral Analysis and Synthesis
Peter Vary, Rainer Martin · 2023
In contrast to the transform-based methods of the previous chapter, in this chapter the authors discuss spectral analysis using narrowband filters. The polyphase network filter bank is a very efficient implementation of the short-term spectral analyzer and the short-term spectral synthesizer. The objective of the quadrature mirror filter approach is the spectral decomposition of the signal x(k) into M = 2 K real-valued sub-band signals with maximum sampling rate decimation as well as the reconstruction (synthesis) of the signal from the sub-band signals. The authors describe a digital filter structure for fixed or adaptive spectral modification of speech and audio signals. It is derived from a reference filter bank and is called filter bank equalizer. Main applications are audio equalization and noise reduction.