Browse Prior Art Database

Automatic Recorder Calibration

IP.com Disclosure Number: IPCOM000088188D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Bappert, J: AUTHOR [+2]

Abstract

Rotating head magnetic recorders can be automatically adapted to plural types of tape formats. That is, a TYPE 1 tape may have a pair of servo tracks 1A and 1B adjacent the longitudinal edges and ID track ID-1 is located just inside one of the servo tracks. In loading a TYPE 1 tape onto a rotating head magnetic recorder, it is desired that the TYPE 1 tape be positioned such that the rotor scans an initial positioning area IPA-1. In this manner a write head on the rotor can read servo signals (low frequency signals) for supplying the signals to control circuits (not shown) to sense and calibrate the exact location of a servo track with respect to the zero position indicator (ZPI) on the tachometer (TACH) of the recorder rotor. Generally, a TYPE 1 format requires that the location of the servo 1A be at time S1A.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 59% of the total text.

Page 1 of 2

Automatic Recorder Calibration

Rotating head magnetic recorders can be automatically adapted to plural types of tape formats. That is, a TYPE 1 tape may have a pair of servo tracks 1A and 1B adjacent the longitudinal edges and ID track ID-1 is located just inside one of the servo tracks. In loading a TYPE 1 tape onto a rotating head magnetic recorder, it is desired that the TYPE 1 tape be positioned such that the rotor scans an initial positioning area IPA-1. In this manner a write head on the rotor can read servo signals (low frequency signals) for supplying the signals to control circuits (not shown) to sense and calibrate the exact location of a servo track with respect to the zero position indicator (ZPI) on the tachometer (TACH) of the recorder rotor. Generally, a TYPE 1 format requires that the location of the servo 1A be at time S1A. Since the exact position of the servo in the time domain is not known, a time window W1 is established in the recorder circuits for finding S1A. Once S1A is identified, all of the other timing of the recorder can be precisely adjusted to the determined S1A for precision recording operations.

A TYPE 2 tape may have an ID track ID-2 located intermediate a servo track 2A and one of the longitudinal edges of the tape. In such a situation the elapsed time between ZPI and the servo track 2A time position S2A is greater than TYPE
1. A time window W2 is established for finding type S2A. Again, once S2A is identified, all of the timing...