The design and implementation of an 11-band phase-linear digital audio equalizer system based on digital signal processing techniques is presented. The design of analog Bessel-Thomson and digital FIR filters for the preservation of phase linearity, and the use of oversampling and decimating techniques resulting in a robust system feasible for hardware implementation are included. Techniques resulting in filter size reduction and in flat composite frequence response (whenever two or more adjacent bands are added together) are also described. The problems encountered in this design can be found in the development of any digital audio system, and the techniques used to solve them could also be efficiently implemented in the development of a system other than the digital equalizer.
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