| 摘要 |
According to this invention, if noise generated by operation of a component such as a rotary drum of a recording/playback apparatus which operates periodically enters a microphone, noise waveforms can be extracted and reduced. Data obtained from microphones (6, 7) are converted into digital data by A/D converters (11, 12) and are supplied to a control microcomputer (5) and adders (15, 16). The control microcomputer (5) has a memory which stores input data for respective mechanical noise generation cycles. The microcomputer (5) calculates the average of inphase data in each cycle, thereby generating only data of noise components and storing the result in memories (13, 14). The adders (15, 16) output data without noise components by subtracting the inphase data stored in the memories (13, 14) from input current data.
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