Helical scan tracking apparatus including means for correcting for track curvature

Patent 4688109 Issued on August 18, 1987. Estimated Expiration Date:

August 18, 2004. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3881184

Automatic scan tracking using a magnetic head supported by a piezoelectric bender element
Patent #: 4151570
Issued on: 04/24/1979
Inventor: Ravizza , et al.

Tracking control system
Patent #: 4438463
Issued on: 03/20/1984
Inventor: Sakamoto

Controlling the trace of a rotary head
Patent #: 4443823
Issued on: 04/17/1984
Inventor: Sakamoto

Scan tracking apparatus for helical scan video tape recorder Patent #: 4520410
Issued on: 05/28/1985
Inventor: Sekiguchi , et al.

Inventor

Sangu, Isao

Application

No. 06/596710 filed on 04/04/1984

US Classes:

386/79, Using control signal on the recording medium360/70, Synchronizing moving-head moving-record recorders360/77.16, Having head deflection drive (e.g., piezoelectric bimorph)386/113, Recorder or reproducer fault condition compensation386/77Having static memory

Examiners

Primary: Cardillo, Raymond F. Jr.
Assistant: Nguyen, Hiep T.

Attorney, Agent or Firm

Ostrolenk, Faber, Gerb & Soffen

International Class

G11B 5/588 (20060101)

Foreign Application Priority Data

1983-04-04 JP

Abstract

A scan tracking circuit for helical scan video tape recorders. The circuit creates and combines three control signals and generates as an output a deflection signal which serves to accurately maintain the scanning head on a desired track. The first control signal is sawtooth shaped and is based upon and derived from the speed of the tape. The second control signal is dependent on the signal which is developed by the scanning head and is also correlated with other signals which are obtained from previous scans of a previous scanned video track. The third signal is selected from a plurality of stored signals each of which is tailored to correct for a characteristic curvature pattern associated with video tracks produced by a particular VTR machine. The final deflection signal is a composite of the three control signals.