GB1128882A - Systems for storing and reproducing intelligence signals - Google Patents

Abstract

1,128,882. Time-control of magnetic recording. INTERNATIONAL STANDARD ELECTRIC CORP. 27 Jan., 1967 [29 Jan., 1966], No. 4170/67. Heading G5R. In apparatus for controlling the rate of flow of information in a train of intelligence signals in the course of being stored on or reproduced from a recording medium, with the aid of a simultaneously or previously stored periodic electric pilot or like signal, the pilot or like signal is split into a delayed and a non-delayed signal, and both these signals are superposed in a phase- or phase-and-frequency comparison circuit for generating a voltage to be used for controlling the rate of information flow; the recording medium is influenced magnetically or otherwise, during relative movement between it and a recording or reproducing element. In the simplest embodiment (Fig. 1, not shown), reproduced pilot, synchronizing and/or subcarrier signals are derived at the output (2) of the read-out head (1) of a storage device, and are split up between a direct path, extending to input (4), and an indirect path via a timedelay arrangement (3) extending to input (5), of a phase-, or phase- and frequency-comparison circuit (6). At the output (7) of this circuit a control voltage is available as a function of the phase or frequency difference, to be used to correct and stabilize the speed of the information flow, e.g. by varying the driving speed of the recording material and/or the recording or read-out head. In Fig. 2 (not shown), the delay arrangement is omitted, but a second read-out head is provided downstream (in relation to recording- material travel) of head (1). Each head is connected directly to one of the two inputs of comparison circuit (6). As shown in Fig. 3, recording head 1 is connected via time-delay arrangement 3, and readout head 8 is connected directly, to comparison circuit 6. The train of signals stored by head 1 on a moving record medium is led in direction 9. The absolute speed of the information flow may be regulated because the transit time of the signal recorded via head 1 up to read-out head 2, and the transit time through the time-delay arrangement 3 are compared with one another, as indicated by the double-headed arrow at 2.