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Active Noise Reduction of Disk drives Disclosure Number: IPCOM000015084D
Original Publication Date: 2001-Sep-13
Included in the Prior Art Database: 2003-Jun-20

Publishing Venue



Disk drive sound level is a consideration in many applications. Current practice in reducing the sound level is to employ passive noise and/or vibration damping materials in the disk drive enclosure. This invention is to use an active noise cancellation technology to reduce the perceived sound level. The basic idea is to use a listenting device to register the sound waveform and then to produce an inverted waveform which is then sent to a sound wave transducer. The coincidence of in-phase and out-of-phase sound waveforms cancels the targeted noise. The noise cancellation can be continuously active in which the anti-noise is produced continuously in response to the noise picked up by the listening device or in a predictive mode in which pre-programmed anti-noise waveforms can be generated. In practice, disk drives and other electronic devices emit distinct noises that can be characterized beforehand, say during product development time. For example, in a hard disk drive the noise sources can come from the spindle motor and the seeking motion of the actuator. The motor noise generally has higher frequency content than the seeking noise. A simple filter in the listening device can easily detect the noise type and a pre-programmed anti-noise waveform can then be generated as long as the detected noise is still present. A salient feature of the invention is that the listening device can be programmed to detect unusual noises such as those generated during controlled crash stops or an HDI (Head Disk Interface) event and to feedback the information to the controller to execute appropriate actions such as power down. On an expanded scale, the active and/or pre-programmed noise cancelling idea can be extended to other electronic boxes such as PCs and storage systems. 1