Patent EP0087907A2 successfully refreshed from Google Patents.
EP0087907A2
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EP
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Calibration system for a magnetic recording apparatus, and calibration arrangement for use with a magnetic storage medium
Assignee: Thales Contact Solutions Ltd
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Filing: 1983-02-22
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Granted: —
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Expires: 2003-02-22
Abstract
Abstract An automatic calibration arrangement for a tape recorder is disclosed. The arrangement includes a microprocessor 36 which responds to pre-stored calibration signals stored in a ROM 38 and a RAM 40 to write predetermined tones onto each track of the tape using the record circuits and record heads of the tape recorder, and then monitors the corresponding signals as replayed by the replay heads and replay circuits of the tape recorder so as to automatically adjust parameters of the record and replay circuits accordingly. The record and replay circuits are arranged to be settable by means of digital numbers produced by the microprocessor. Parameters which may be adjusted include record bias, record drive current (to produce 1% third harmonic distortion), and the mid band and band edge filter circuits, and phase adjustment of the replay circuits. Recorders not having replay circuits (but having replay heads) can still have their bias level and record current calibrated and can record replay calibration frequencies for external calibration purposes.
Inventors
- 👤 Neil Martyn Crick
- 👤 Anthony Miles
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 08:39
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/02; G11B20/025; G11B20/10; G11B20/18; G11B20/1816; G11B20/182; G11B27/00; G11B27/36
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
58 words
An automatic calibration system for calibrating circuitry in magnetic recording apparatus, in which a pre-stored signal is automatically recorded by the apparatus onto a magnetic storage medium via the recording circuitry (10) of the apparatus, the recorded signal being monitored and its value used to adjust at least one predetermined parameter (50, 62) of the recording circuitry (10).
Claim 2
Dependent Claim
58 words
An automatic calibration system for calibrating circuitry in magnetic recording apparatus, in which a pre-stored signal is automatically recorded by the apparatus onto a magnetic storage medium via the recording circuitry (10) of the apparatus, the recorded signal being monitored and its value used to adjust at least one predetermined parameter (50, 62) of the recording circuitry (10).
Claim 3
Dependent Claim
62 words
A system according to claim 1, in which the recorded signal is replayed by replay circuitry (23) of that apparatus, or by replay circuitry of other apparatus to which the magnetic storage medium has been transferred, and the replayed signal monitored and its value used to calibrate a parameter (76, 78, 80, 82) of the replay circuitry (23) of the replaying apparatus.
Claim 4
Dependent Claim
123 words
An automatic calibrating arrangement for use with and incorporated in a magnetic storage medium, comprising a non-volatile store (38, 40) in the recorder storing a plurality of predetermined calibration and control signals, control means (36) responsive to the pre-stored signals to read them out in a predetermined sequence and, in response thereto, to energise the recording circuitry (10) of the recorder so as to record on the magnetic storage medium calibration signals having predetermined characteristics, the control means (36) being operative to monitor the value of the recorded signals and to calibrate the bias level (50) applied to the record head (12) by the recording circuitry (10) to a predetermined value and to calibrate the record current (62) of the recording circuitry (10).
Claim 5
Dependent Claim
123 words
An automatic calibrating arrangement for use with and incorporated in a magnetic storage medium, comprising a non-volatile store (38, 40) in the recorder storing a plurality of predetermined calibration and control signals, control means (36) responsive to the pre-stored signals to read them out in a predetermined sequence and, in response thereto, to energise the recording circuitry (10) of the recorder so as to record on the magnetic storage medium calibration signals having predetermined characteristics, the control means (36) being operative to monitor the value of the recorded signals and to calibrate the bias level (50) applied to the record head (12) by the recording circuitry (10) to a predetermined value and to calibrate the record current (62) of the recording circuitry (10).
Claim 6
Dependent Claim
114 words
An arrangement according to claim 3, in which, in order to calibrate the bias applied to the record head (12) to the predetermined level, the control means (36) is operative in response to the pre-stored calibration signals to apply a substantially constant amplitude record signal to the input of the recording circuitry and, simultaneously, to increase the bias applied to the record head from a relatively low level towards the maximum level, the control means being operative to monitor the magnitude of the corresponding signal replayed from the storage medium so as to detect when the level thereof corresponds to an optimum value for the bias and to set the bias at that level.
Claim 7
Dependent Claim
34 words
An arrangement according to claim 4, in which the optimum level of the bias corresponds to a value of the replayed signal which is less by a predetermined amount than the peak value thereof.
Claim 8
Dependent Claim
127 words
An arrangement according to any one of claims 3 to 5, in which, in order to calibrate the record current of the recording circuitry, the control means (36) is operative in response to the pre-stored calibration signals to record a signal on the magnetic storage medium at a predetermined frequency by means of the recording circuitry (10) and the record head (12), and to monitor the value of the third harmonic of the predetermined frequency, as replayed by the replay head (21) of the recorder, while the drive current to the record head is changed, so as to determine the value of the record current when the level of the third harmonic current reaches a predetermined limit and to calibrate the record current (62) to that value.
Claim 9
Dependent Claim
49 words
An arrangement according to claim 6, in which the control means comprises means for measuring the level third harmonic of the predetermined frequency in the form of means (34) for comparing the level of the third harmonic at that frequency with the level of the fundamental at that frequency.
Claim 10
Dependent Claim
37 words
8, An arrangement according to any one of claims 3 to 7, in which the recording circuitry (10) comprises circuitry parameters whereof are adjustable by means of digital control signals which are produced by the control means.
Claim 11
Dependent Claim
116 words
An arrangement according to any one of claims 3 to 8, in which the control means (36) is operative in response to the pre-stored calibration signals to record on the magnetic storage medium, by means of the record head (12) and the recording circuitry (10), a sequence of signals at different predetermined frequencies which are positioned adjacent the lower end, the upper end and between those ends, of a frequency band of the recorder and at predetermined amplitudes, and is operative in response to the magnitude of the replayed signals as replayed by the replay head (21) and replay circuitry (23), to automatically adjust the replay circuitry (23) so that the replayed signals have predetermined magnitudes.
Claim 12
Dependent Claim
98 words
An arrangement according to claim 9, in which the control means (36) also includes means responsive to the pre-stored calibration signals for recording on the magnetic storage medium, by means of the record head (12) of the recording circuitry (10), a signal consisting of a substantially rectangular wave at a predetermined frequency and with a predetermined amplitude, and is operative in response to the corresponding replayed signal as replayed by the replay head (21) and replay circuitry (23) to adjust the phase (82) of the replayed signal until the magnitude of the replayed signal is at a minimum.
Claim 13
Dependent Claim
81 words
An arrangement according to any one of claims 3 to 10, in which the recorder is a multi-channel magnetic tape recorder having a plurality of record heads (12) each with its associated circuitry (10) and the automatic calibration arrangement is operative to record the calibration signals on a plurality of tracks on the magnetic tape using the corresponding record heads (12) and to calibrate the bias level and the record current in the recording circuitry (10) corresponding to each such head.
References Cited (Backward Citations)
No citation records indexed.
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