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Self-Contained Acoustic Crash Detect Device for Magnetic Disk Storage Recording Device

IP.com Disclosure Number: IPCOM000039630D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Larson, TS: AUTHOR

Abstract

A crash detection device shuts down a magnetic disk storage recording file before data is lost in the event of the head coming in contact with the disk (a head crash). The crash detection device includes a circuit that only requires a single 5-volt power supply and a 36 KHz bandpass filter. The single 5-volt power supply allows circuit application to be very flexible. The bandpass filter ascertains that only wanted frequencies are allowed through for accurate and precise signal output. The crash detection device also includes a microphone and the circuit and microphone are small enough that they could easily be installed as an integral part of the existing electronics for the disk storage recording device. (Image Omitted) A head crash emits ultrasonic vibrations at various frequencies 22.5, 36 and 42.5 KHz, Figs. 1 and 1C.

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Self-Contained Acoustic Crash Detect Device for Magnetic Disk Storage Recording Device

A crash detection device shuts down a magnetic disk storage recording file before data is lost in the event of the head coming in contact with the disk (a head crash). The crash detection device includes a circuit that only requires a single 5-volt power supply and a 36 KHz bandpass filter. The single 5-volt power supply allows circuit application to be very flexible. The bandpass filter ascertains that only wanted frequencies are allowed through for accurate and precise signal output. The crash detection device also includes a microphone and the circuit and microphone are small enough that they could easily be installed as an integral part of the existing electronics for the disk storage recording device.

(Image Omitted)

A head crash emits ultrasonic vibrations at various frequencies 22.5, 36 and
42.5 KHz, Figs. 1 and 1C. An ultrasonic transducer can detect the frequencies in this range, Fig. 1A, showing that the ultrasonic microphone is a wide bandpass filter in itself. The signal produced by a head crash is applied to the circuit in Fig. 2 where the circuit narrow bandpasses the signal which is tuned to 36 KHz. The filtered signal is then rectified and converted to a DC level. This DC voltage increases proportionally to the increase in signal amplitude. The DC voltage is then amplified and compared to a known voltage reference, which will then output a logic level change of...