Time difference slow mode control circuit
AssigneeSamsung Electronics Co., Ltd.
InventorHee-Man Kim
Life of this patent
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Abstract
A time difference slow mode control circuit of a video tape recorder for controlling a capstan motor by picking up the reproduction control signal from a magnetic tape, in the time difference slow mode, generates delayed phase-delayed pseudo reproduction control signal by a half period of a head switching pulse, the frequency of the pseudo reproduction control signal being the same as that of the reproduction control signal, thus controlling the capstan motor so that the video tape recorder may have a normal time difference slow mode even when a pick-up error arises and thereby improving screen quality.
Claims22
A time difference slow mode control circuit of a video tape recorder having a normal mode of reproduction and a time difference slow mode wherein a capstan motor alternately stops and rotates to make video images appear to move in slow motion, said video tape recorder having servo means for generating a head switching pulse and for amplifying a reproduction control signal picked up by an audio/control head of the video tape recorder, said servo means controlling the capstan motor in response to time difference slow mode control signals, and a microcomputer generating said time difference slow mode control signals in response to said reproduction control signal, to control said servo means, said time difference slow mode control circuit comprising:
- pseudo reproduction control signal generating means for generating a pseudo reproduction control signal in response to said head switching pulse;
- and
- switching means for enabling transmission of said reproduction control signal to said microcomputer when said reproduction control signal is picked up, and for enabling transmission of said pseudo reproduction control signal to said microcomputer to enable generation of said time difference slow mode control signals when said reproduction control signal is not picked up, during said time difference slow mode.
The time difference slow mode control circuit as claimed in 10, wherein said pseudo reproduction control signal is phase delayed by one-half of a period of said head switching pulse.
A method for providing a microcomputer of a video tape recorder with a pseudo reproduction control signal during a time difference slow mode wherein a capstan motor alternately stops and rotates in order to make video images appear to move in slow motion, in order to compensate for reproduction control signal error, said method comprising the steps of:
- generating a pseudo reproduction control signal in response to a head switching pulse amplified by a servo of the video tape recorder;
- delivering said pseudo reproduction control signal to said microcomputer, during said time difference slow mode when a reproduction control signal is not picked up by an audio/control head;
- delivering said reproduction control signal to said microprocessor, during said time difference slow mode when said reproduction control signal is picked up by said audio/control head;
- generating time difference slow mode control signals in response to said reproduction control signal and said pseudo reproduction control signal;
- and
- driving the capstan motor in response to said time difference slow mode control signals.
A control circuit for controlling a capstan motor of a video tape recorder during a time difference slow mode wherein the capstan motor alternately stops and rotates in order to make video images appear to move in slow motion, said control circuit comprising:
- servo means for generating a head switching pulse, for amplifying a reproduction control signal received from an audio/control head, and for driving the capstan motor in response to time difference slow mode control signals;
- pseudo reproduction control signal generating means for generating a pseudo reproduction control signal in response to said head switching pulse;
- switch means for alternately enabling transmission of one of said reproduction control signal and said pseudo reproduction control signal during said time difference slow mode in dependence upon receipt of said reproduction control signal by said switch means, to generate a capstan control signal;
- and
- microprocessing means for generating said time difference slow mode control signals in response to said capstan control signal.
Dependencies are inferred from the claim text.