4,624,894

43.88.Qg MAGNETIC RECORDING MEDIUM

4,635,153

43.88.Qg MAGNETIC TRANSDUCER HEAD

Mikio Kishimoto, assignor to Hitachi Maxell, Ltd. 25 November 1986 (Class 428/328); filed in Japan 6 April 1984

This tape has two magnetic layers: An underlayer of acicular metal particles such as Fe-Co alloy oriented in a parallel direction while suspend- ed in an organic polymer binder; and a top layer of plate-shaped barium ferrite particles having a magnetic preferred direction perpendicular to sur- face of the plates. The tape made in this way has a uniform response to long- wavelength as well as short-wavelength recordings.--MC

Toshiki Shimamura and Kiyonori Hayakawa, assignors to Sony Corporation

6 January 1987 (Class 360/125); filed in Japan 30 August 1982

This head uses a thin stylus for recording on magnetic media that have perpendicularly oriented particles. The stylus is made by depositing a thin film of permalloy on a polished member. The stylus is then sandwiched between magnetic ferrite blocks, shaped to reinforce the magnetic circuit near the working tip and also to form a diffuse magnetic return circuit on each side of the tape path near the tip.--MC

4,625,245

43.88.Qg MAGNETIC RECORDING

R. Kent White, Ft. Washington, MD 25 November 1986 {Class 360/40); filed 8 November 1984

Instead of continuous signals to a magnetic recording head, this patent uses short duration pulses, with intervals between pulses approximately equal to the time taken for the tape to traverse the head gap. Advantages are lower power consumed in recording, and reduced demagnetization by the fringing field at the head gap.--MC

4,625,250

43.88.Qg MULTI-TRACK MAGNETIC HEAD

Norio Shibata, assignor to Victor Company of Japan

25 November 1986 (Class 360/121); filed in Japan 7 January 1982

Half of this head is made by thin film deposition techniques where multiple cores and insulating films are deposited through masks on a fiat substrate. The second half, which mates with the above, is an assembly of separate "block" cores and windings made by conventional nondeposition methods. Alternatively, the windings may be deposited on the first half. The hybrid techniques yield heads of higher efficiency than can be made by film deposition alone.--MC

4,635,143

43.88.Qg WAVEFORM EQUALIZER FOR SIGNAL REPRODUCED FROM MAGNETIC RECORDING MEDIUM

Hiroshi Suzuki and Makoto Imamura, assignors to Kabushiki Kaisha Toshiba

6 January 1987 (Class 360/65); filed in Japan 30 June 1983

When a perpendicular recording is reproduced with a ring head, the playback contains a longitudinal component that interferes with the purity of the perpendicular component. The longitudinal portion can be corrected with an equalizer containing a tapped delay line, short-circuited at its far end, and with a weighting adder for adjusting the signals picked up from taps on the delay line.--MC

4,635,144

43.88.Qg TAPE RUNNING CONTROL APPARATUS FOR AUDIO TAPE RECORDER

Hideaki Goto and Ichiro Ninomiya, assignors to Sony Corporation 6 January 1987 (Class 360/72.2); filed in Japan 25 October 1983

A tape recorder is automatically cued to a desired selection by a time code recorded on the tape that is compared with a preset code. To reduce wear, the head is lifted from the tape while in the high-speed searching mode; but occasionally the head is brought into contact with the tape for a brief sampling of time code. When the samples indicate closeness to the required position, the tape is slowed down and the head remains in contact for precise positioning.--MC

4,636,448

43.88.Qg MAGNETIC RECORDING MEDIUM Haruyuki Morita, Jiro Yoshinari, and Kazumasa Fukuda, assignors

to TDK Corporation 13 January 1987 {Class 428/607); filed in Japan 26 January 1984

The uniformity of a recording layer designed for perpendicular magne- tization is disturbed if its permeable underlayer is too coarse. This patent describes the use of a sputtered underlayer havidg an average grain diameter less than half of that in the recording layer.•MC

4,636,897

43.88.Qg PERPENDICULAR MAGNETIC RECORDING AND REPRODUCING THIN FILM HEAD

Hitoshi Nakamura et aL, assignors to Hitachi, Ltd. 13 January 1987 {Class 360/119); filed in Japan 15 October 1982

This head, useful for perpendicular magnetic recording media, is made by successive deposition of thin films on a very fiat substrate. Its improve- ment over prior thin-film heads is to deposit the main magnetic polepiece first, and to step down the thickness of this polepiece to a fine knife•edge 0.1 to 1.0 pm thick. This is followed by an insulating gap layer, and by the second magnetic polepiece 5 to 40 pm thick. Prior heads had the main polepiece deposited last, which decreased its precision due to cumulative inaccuracies in the layers below it.•MC

4,636,886

43.88.Qg ROTARY HEAD RECORDING SYSTEM

Theodore A. Schwartz, assignor to Magnetic Peripherals, Incorporat- ed

13 January 1987 {Class 360/84); filed 2 August 1984

The advent of digital audio recording makes rotary head recorders important for audio, where, previously, rotary heads were used mainly in

14 30 !7

29 15

17 18 16

1870 J. Acoust. Soc. Am. 82(5), Nov. 1987; 0001-4966/87/111870-02500.80; @ 1987 Acoust. Soc. Am.; Patent Reviews 1870

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 129.120.242.61 On: Mon, 24 Nov 2014 14:12:20