Development of parametric equalizer LSI

A novel parameteric equalizer LSI that features advanced functions and improved cost performance is described. The development objectives were to: (1) improve functional levels to exceed those of conventional graphic equalizers; (2) miniaturize all hardware components in a small package; (3) minimize required external parts; (4) improve operability and processing speed; and (5) maintain the performance of discrete systems. The parametric equalizer LSI has the following functions: (1) controls 8-band stereo sound; (2) controls center frequency in 11 steps (1/3 octave between steps); (3) sets gain to one of 13 positions (in steps of 2 dB); (4) adjusts resonance sharpness in 8 steps from 1/6 to 3 octaves; and (5) selects peaking or shelving for high and low bands