Continuous frequency dynamic range audio compressor
June 6, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesDigital system for changing the rate of recorded speech Hearing aid amplifier Signal compression system Automatic gain control for hearing aid Adaptive sample rate based on input signal bandwidth Phonetic equalizer system Nonlinear method and apparatus for coding and decoding acoustic signals with data compression and noise suppression using cochlear filters, wavelet analysis, and irregular sampling reconstruction Hearing aid device incorporating signal processing techniques Programmable digital hearing aid Adaptive filter for signal processing and method therefor Patent #: 5694474 InventorsAssigneeApplicationNo. 870426 filed on 06/06/1997US Classes:381/315, Remote control, wireless, or alarm381/313DirectionalExaminersPrimary: Kuntz, CurtisAssistant: Harvey, Dionne Attorney, Agent or FirmForeign Patent References
International ClassH04R 025/00AbstractAn improved multiband audio compressor is well behaved for both wide band and narrow band signals, and shows no undesirable artifacts at filter crossover frequencies. The compressor includes a heavily overlapped filter bank, which is the heart of the present invention. The filter bank filters the input signal into a number of heavily overlapping frequency bands. Sufficient overlapping of the frequency bands reduces the ripple in the frequency response, given a slowly swept sine wave input signal, to below about 2 dB, 1 dB, or even 0.5 dB or less with increasing amount of overlap in the bands. Each band is fed into a power estimator, which integrates the power of the band and generates a power signal. Each power signal is passed to a dynamic range compression gain calculation block, which calculates a gain based upon the power signal. Each band is multiplied by its respective gain in order to generate scaled bands. The scaled bands are then summed to generate an output signal.Other References
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