GB1227895A - - Google Patents

Abstract

1,227,895. Video magnetic tape apparatus. GRUNDIG E.M.V. ELEKTRO MECHANISCHE VERSUGHSANSTALT INH. MAX GRUNDIG. 3 Oct., 1969 [4 Oct., 1968], No. 48659/69: Heading G5R. In apparatus for recording and reproducing television video signals, the tape/head speed synchronizing square-wave signals (Fig. 3a, not shown) (corresponding to the frame frequency), whose repetition frequency is at the lower limit of the recordable frequency band, are converted into pulses of decaying wave trains of a higher wave frequency. A capacitor 3 and the inductive head 4, Fig. 2 or 4, form a circuit resonant at the optimum response frequency of the playback head, so that each edge of the square-wave appearing across the resistor 2, Fig. 2, from the emitter of transistor 1 produces a pulse at that frequency. The circuit of Fig. 4 suppresses either the leading or the trailing edge of each pulse (Fig. 3c and 3d, not shown) so that the frequency of repetition of the pulses equals that of the square-wave. For reproducing the synchronizing signals, a tuned playback amplifier may be connected at the junction point between capacitor 3 and head 4, which then form a parallel resonant circuit. The usual H.F. bias may be applied at the junction between 3 and 4.