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1. (WO2015125195) AUDIO SIGNAL AMPLIFICATION APPARATUS

Pub. No.:    WO/2015/125195    International Application No.:    PCT/JP2014/005914
Publication Date: Fri Aug 28 01:59:59 CEST 2015 International Filing Date: Thu Nov 27 00:59:59 CET 2014
IPC: H03F 3/217
H03F 1/32
Applicants: PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.
パナソニックIPマネジメント株式会社
Inventors: IWATA, Kazuya
岩田 和也
Title: AUDIO SIGNAL AMPLIFICATION APPARATUS
Abstract:
An audio signal amplification apparatus of the present disclosure comprises: a delta-sigma modulation unit that re-samples an input digital audio signal by use of a quantization number smaller than the quantization number of the digital audio signal; a pulse width modulation unit that converts the gradation in the amplitude direction of an output signal of the delta-sigma modulation unit to gradation in pulse width, thereby generating a pulse width modulation signal; a power amplification unit that power-amplifies the output signal of the pulse width modulation unit; a low-pass filter that diminishes those components of the output signal of the power amplification unit which are higher than a predetermined cutoff frequency; and a correction processing unit that generates a correction signal for correcting the digital audio signal. The correction processing unit includes a switch for turning on/off the connection to the low-pass filter. During the on-state of the switch, the correction processing unit connects a speaker to the low-pass filter and generates the correction signal.