JPS623174U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a circuit diagram showing a specific example of the pseudo vertical synchronization signal generator and timing correction circuit shown in FIG. 1, FIG. 3 is a waveform diagram for explaining the operation of the embodiment shown in FIG. 2, and FIG. is a circuit diagram showing another embodiment of the pseudo vertical synchronization signal generator and timing correction circuit, FIG. 5 is a waveform diagram for explaining the operation of the embodiment shown in FIG. 4, and FIG. FIG. 7 is a diagram showing the arrangement of rotating magnetic heads for performing H alignment correction, and FIG. 8 is a characteristic diagram for explaining H alignment correction. Explanation of symbols, 1... Pseudo vertical synchronization signal generator,
2... Pseudo vertical synchronization signal inserter, 3... Timing correction circuit, 5... Pulse generator.

Claims (1)

[Scope of utility model registration request] In a helical scan video tape recorder, a sawtooth wave generator includes an integrating circuit and outputs a sawtooth wave having a cycle of one field scanning time based on a head switching pulse during still playback;
a pseudo vertical synchronization output generator that detects that the voltage level of the sawtooth wave has reached a voltage level corresponding to a vertical synchronization signal position within one field and outputs a pseudo vertical synchronization signal; and the sawtooth wave generator. a charge correction circuit that corrects the charging speed of the capacitor constituting the integrating circuit; a changeover switch that controls the operation/non-operation of the charge correction circuit; A video tape recorder comprising a control circuit for operating a switch.