Adaptive noise reduction method and device

Abstract

A variable cycle pulse signal and a sampling clock are input to counter means (32) in an adaptive signal processing . The input cycle is counted by the sampling clock and the count value is input to timing generation means (34). From this timing pulse, an XV address (successively from 0 to M) is generated by variable read address generation means (33) and an Xk-1 address (successively from 0 to M) is generated by write address generation means (35). They are input as a read address and a write address of an accumulator (36). Thus, the noise waveform pitch to be subtracted is changed under control of the DVD-RAM disc motor and the other motor rpm and following the cycle change of the motor noise generated when the rotation cycle is changed such as upon motor start. Accordingly, there is almost no need of adaptive filter coefficient updating and it is possible to reduce the noise without decreasing the noise cancel effect.

Description

technical field [0001] The present invention relates to an adaptive noise attenuation method and apparatus capable of performing adaptive noise attenuation satisfactorily, even with variable period noise. In such variable-period noise, the period of the target noise varies, and the present invention particularly relates to an adaptive noise attenuation method and device, which are suitable for attenuating electromagnetic noise, noise, vibration noise and the like, which originate in Noise of a drive disc motor that rotates a digital versatile disc random access memory (hereinafter abbreviated as DVD-RAM). Background technique [0002] For example, in Japanese Patent Application No. H11-176113 published in Japanese Patent Application No. H11-176113, a synchronous adaptive filter is proposed that can eliminate from the main input Hereinafter referred to as VRT) periodic noise on the drum motor. In the technology disclosed in this gazette, an adaptive filter is used, and the ...

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Problems solved by technology

Thus, the rotational speed must be changed rapidly when moving between sectors during the seek time, causing the aforementioned variable period noise to appear depending on changes in rotational speed

In addition, even when the rotation speed control system is a conventional CLV system, the number of rotations changes rapidly at the time of seek, etc., so variable cycle noise will appear depending on the change in rotation speed

[0033] In view of the above-mentioned points and objectives, the present application is proposed in order to solve such a problem that it is difficult to make the adaptive filter coefficient change rapidly and the variable period noise whose period changes rapidly with the conventional adaptive noise reduction method and equipment. follower, such that it is impossible to effectively attenuate variable period noise from the main input

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