Tandberg Data As

Tandberg Data Asa

Erik N Hardeng

Georg Boasson

A speed servo control for a tape drive comprising a take up reel having tape wound therearound, the tape extending to a supply reel and wound therearound. A flutter roller is arranged to press said tape that extends between the take up reel and the supply reel to rotate with circulation of the tape. A first tachometer is connected to said take up reel to rotate therewith. A second tachometer is connected to the flutter roller to rotate therewith, the first and second tachometers connected to a servo system for controlling the speed of the take up reel drive motor according to the select speed of the tape. The second tachometer from the flutter roller normally controls the servo for controlling the take up reel speed. A mechanism is provided for ignoring a tachometer signal from the second tachometer and controlling using the first tachometer, until the tape is tensioned against the flutter roller after start up. The mechanism for ignoring is advantageously a third tachometer connected to the supply reel and a pulse detector sensing pulses from the third tachometer and signal connected to the switch such that when a certain number of tachometer pulses are sensed from the third tachometer, or a certain stable frequency of pulses is sensed from the third tachometer, the switch is switched from the first tachometer (take up reel) as input, to the second tachometer (flutter roller) as input to the servo system.

Tape drive start up and stop tape speed control

A method and an apparatus for recording data information on a magnetic recording medium with the assistance of a magnetic write head and a controllable record amplifier preceding the magnetic write head and to which the data information in the form of binary data signals, as well as bias signals superimposed thereon are supplied, are disclosed. The recorded signals are, in turn, read with a playback device immediately after the recording. In a measuring device, the peak shift of the read output signals is measured and averaged. The amplitudes for the binary data signals and/or of the bias signals are corrected with a control signal generated by a control unit dependent on the average peak shift, being corrected in order to achieve an optimum relationship of read output signal amplitude to minimum peak shift.

Method and apparatus for recording data information on a magnetic

In an arrangement for recording data or a magnetic recording medium, the inputs of an amplifier whose outputs are connected to a magnetic head are preceded by filters which delay magnetic bias signals and data signals supplied to the amplifier and limit their steepness. Undesirably high voltages at the magnetic head as a consequence of excessively steep edges of a write current supplied to the magnetic head are thus avoided, and the reliability of the recording of the data on the magnetic recording medium is increased.

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Olso, Norway

Erik N Hardeng