Time changing system for VTR

An apparatus for controlling the playback speed of a video tape recorder to conform to a selected speed different from a recording speed, said apparatus comprising means for generating a signal having a frequency in accordance with said selected playback speed, a servo circuit, means for applying said signal as a reference signal to said servo circuit, said servo circuit providing an output signal for control of said playback speed to conform to said selected speed, whereby a reproduced video signal recorded in accordance with a frame rate no longer conforms to said frame rate, and means for converting the reproduced video signal to conform to a selected frame rate, said generating means comprising means for calculating the quotient of a normal playback time of a length of video tape to a desired playback time, an oscillator means for providing said reference signal, and means for controlling the frequency of said oscillator means in accordance with said quotient.

A method for controlling the playback speed of a video tape recorder to conform to a selected speed different from a recording speed, said method comprising generating a signal having a frequency in accordance with said selected playback speed, applying said signal as a reference signal to a servo circuit, providing an output signal from said servo circuit for control of said playback speed to conform to said selected speed, whereby a reproduced video signal recorded in accordance with a frame rate no longer conforms to said frame rate, and converting the reproduced video signal to conform to a selected frame rate, said generating step comprising calculating desired playback time of a length of video tape using end and real times of said length, calculating the quotient of normal playback time to desired playback time, and controlling the frequency of an oscillator in accordance with said quotient.

An apparatus for controlling the playback speed of a video tape recorder to conform to a selected speed different from a recording speed, said apparatus comprising means for generating a signal having a frequency in accordance with said selected playback speed, a servo circuit, means for applying said signal as a reference signal to said servo circuit, said servo circuit providing an output signal for control of said playback speed to conform to said selected speed, whereby a reproduced video signal recorded in accordance with a frame rate no longer conforms to said frame rate, and means for converting the reproduced video signal to conform to a selected frame rate, said generating means comprising means for calculating desired playback time of a length of video tape using said end and real times of said length, means for calculating the quotient of normal playback time to desired playback time, an oscillator means for providing said reference signal, and means for controlling the frequency of said oscillator means in accordance with said quotient.