4,815,143

43.88.Kb WIRELESS MICROPHONE

Robert L. Derhang and Donald A. Kutz, assignors to HM Electronics, Incorporated

21 March 1989 (Class 381/168); filed 27 March 1987

The external construction of this microphone addresses the problem of inadvertent mis-sctting or misuse of controls by a performer by placing the on/off control button and detent, and a mute control button and locking detent, out of contact with the user's fingcrs.--MDB

4,814,238

43.88.Qg MAGNETO-OPTICAL RECORDING MEDIUM

Shinsuke Tanaka, Nobutake Imamura and Chuichi Ota, assignors to Kokusai Denshin Denwa Kabushika Kaisha

21 March 1989 (Class 4287692); filed in Japan 6 October 1983

Magneto-optical recording does not require a magnetic head in contact with the record surface, but uses a laser beam that is focused on a micron size area of recording material that has a low temperature Curie point. An advantageous material described in this patent is an amorphous alloy thin film containing a rare earth element such as Tb, a 3d transition metal such as Fe, and a semimetal-semiconductor element such as Si. Such a combination prevents the amorphous alloy from crystallization after repeated recordings and erasings.--MC

LASER BEAM

22

X E::::•

cooled by a water jacket 25. After a first coating is evaporated, a second coating is applied by the same process, using an alloy bar 23 similar to the above but also containing 0.5% to 15% carbon. The result is a vertical magnetic medium of high durability.--MC

4,818,606

43.88.Qg HIGHLY RUNNING-ENDURANT MAGNETIC RECORDING MEDIUM

Noboru Koyama, Shu Ishiguro and Ryosuke Isobe, assignors to Kon- ica Corporation

4 April 1989 (Class 428/323); filed in Japan 2 December 1986

A magnetic coating for recording tape of high wearing resistance and high recording density contains ferromagnetic metal powder, aluminum, a fatty acid, an ester of fatty acid, and carbon black, all in fine particle form and in controlled proportions.--MC

4,819,087

43.88.Qg SYSTEM FOR PRECISELY EDITING AUDIO SIGNALS ON A VIDEOTAPE

4,821,134

43.88.Qg MAGNETIC ALLOY R/W HEAD WITH CENTRALLY PINCHED AND END SLOTTED CORE

Yoshikazu Niwa, assignor to Mitsubishi Denki Kabushiki Kaisha 11 April 1989 {Class 360/122}; filed in Japan 14 November 1985

This head for magnetic recorders reduces the eddy current losses by grooves cut into each core-half at 16, 16, the grooves being filled with glass.

Hajime Takeuchi and Katsuichi Tachi, assignors to Sony Corporation 4 April 1989 (Class 360/14.3); filed in Japan 22 January 1981

The audio signals are recorded longitudinally on a videotape, along with a time code for precisely locating a desired point. A speed changer, pulse generator, record-play mode selector and memory are included to operate a controller that switches over the mode at the selected edit point.. MC

4,814,239

43.88.Qg VERTICAL MAGNETIC RECORDING MEDIUM AND METHOD OF MANUFACTURING THE

SAME

Kazuo Inoue et al., assignors to Ube Industries, Ltd. 21 March 1989 (Class 428/694); filed in Japan 24 March 1987

A magnetic recording tape or disc 24 is manufactured in a vacuum chamber 26 by evaporating on its surface the vapor from an alloy bar 23 heated by a laser beam focused on it by a mirror 22. The bar is made of 50% to 90% cobalt, 8% to 25% chromium, and 1.3% to 15% tungsten. It is

The metallic portions 1, 10, converge at the middle to form a record-play gap 8, which is reinforced at its sides by glass members 13, 13.--MC

4,862,110

43.88.Rh OSCILLATOR, IN PARTICULAR A SURFACE ACOUSTIC WAVE OSCILLATOR, FREQUENCY CONTROLLED BY CONTROLLING ITS TEMPERATURE

Roger Charbonnier, assignor to Schlumberger Industries 29 August 1989 (Class 331/70); filed in France 18 February 1988

This is a technique for coarse tuning a surface acoustic wave (SAW) oscillator by adding a heater (electric) to bring the frequency close enough to a desired frequency so that a conventional electric control loop will lock on. One stated advantage is that it will increase the manufacturing yield of SAW oscillators since out-of-range specimens are currently discarded.-- JWD

2921 J. Acoust. Soc. Am. 88(6), Dec. 1990; 0001-4966/90/122921-01 $00.80; © 1990 Acoust. Soc. Am.; Patent Reviews 2921

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