US 5,986,846 A · Methods and apparatus for track centering an arcuate scanner head assembly

Abstract

A servoing system is provided for use in an arcuate scanner having an arcuate scanner head assembly (ASHA) that has least one transducer on a rotatable drum. The servoing system includes a first detection circuit, a second detection circuit, logic, and a positioning apparatus. The first detection circuit is coupled to the transducer and detects alignment identifiers that are recorded on the tape and sensed by the transducer. The second detection circuit is also coupled to the transducer and detects an envelope of the scanned signal during the scan. The logic compares the alignment identifiers to determine if the ASHA is properly aligned with the tracks on the tape, and in response outputs a fine error signal. The logic also compares the envelope as detected during the scan with a threshold value and outputs a coarse error signal in response. Based on the arrangement of the logic, the fine error signal identifies that either a minor misalignment of the transducer to the tape exists or a proper alignment exists. The coarse error signal identifies that a significant misalignment of the transducer to the tape exists. The positioning apparatus, in response to either the fine error signal or coarse error signal, changes the position of the arcuate scanner head assembly with respect to the tape as a function of the received error signal.

Claims21

Dependent claims

A method for correcting the alignment of an arcuate scanner head assembly to arcuate tracks on a tape, the method comprising:

causing a transducer located on a rotating drum of the arcuate scanner head assembly to sense changes in magnetic flux recorded in at least one of the arcuate tracks on the tape during a pass of the transducer across the tape and output a corresponding signal;
detecting an envelope of the signal associated with the at least one arcuate track during the pass of the transducer across the tape;
comparing said envelope to a threshold value;
and
causing a position of the arcuate scanner head assembly to change if the envelope breaches the threshold value during the pass of the transducer across the tape.

2 more elements

A servoing system for use in an arcuate scanner having an arcuate scanner head assembly that includes at least one transducer on a rotatable drum, the transducer being suitable for reading an arcuate shaped track recorded on a tape, the servoing system comprising:

a first detection circuit coupled to the transducer and configured to detect a first alignment identifier and a second alignment identifier within a scanned signal from the transducer during a scan of the transducer over an arcuate shaped portion of the tape containing the track, wherein each of the alignment identifiers are recorded on the tape;
a second detection circuit coupled to the transducer and configured to detect an envelope of the scanned signal during the scan over the arcuate shaped portion of the tape;
logic coupled to the first and second detection circuits, the logic being configured to compare the first and second alignment identifiers as detected during the scan and output a fine error signal based thereon, and compare the envelope as detected during the scan over the arcuate shaped portion of the tape to a threshold value and output a coarse error signal based thereon, and wherein the fine error signal identifies a minor misalignment of the transducer to the tape, and the coarse error signal identifies a significant misalignment of the transducer to the tape;
and
positioning means coupled to the logic and the arcuate scanner head assembly, the positioning means being responsive to at least one of the fine error and course error signals and configured to change a position of the arcuate scanner head assembly with respect to the tape based thereon.

2 more elements

Dependencies are inferred from the claim text.

Methods and apparatus for track centering an arcuate scanner head assembly

Life of this patent

Methods and apparatus for track centering an arcuate scanner head assembly

Life of this patent

Abstract

Claims21