Apparatus for reproducing magnetically recorded video signal

Claim 1

An apparatus for reproducing a video signal using a rotatable head for reproducing including at least two heads which can be alternately changed over by means of a head changeover signal, from a magnetic recording medium in which four kinds of pilot signals are each sequentially recorded in each track in superposition on a video signal sequentially recorded in each recording track disposed adjacent to each other by a helical scan method, sequentially in each field either at relatively fast standard playing speed or at relatively slow long playing speed, comprising; transferring means for transferring said magnetic recording medium, transfer speed changing means coupled to said transferring means for changing a transfer speed of said magnetic recording medium to either the standard playing speed or the long playing speed so as to adapt the reproducing speed to the speed at which the video signal was recorded, reproduced pilot signal generating means coupled to said rotatable head for reproducing for extracting said pilot signals from the signal reproduced by said rotatable head for providing reproduced pilot signals, reference signal generating means for sequentially providing four types of reference signals having different frequencies in response to said head changeover signal of at least two heads, said four types of reference signal being selected in the frequencies equal to those of said four types of pilot signals, comparing signal generating means coupled to said reproduced pilot signal generating means and said reference signal generating means for mixing said reproduced pilot signal and said reference signal for providing a comparing signal for detecting the level of said beat signal, tracking signal generating means coupled to said comparing signal generating means for generating the tracking signal responsive to the comparing output of said comparing signal generating means, fundamental cycle detecting means coupled to said tracking signal generating means for detecting a fundamental cycle of a comparing signal provided by said generating means, counting means coupled to said fundamental cycle detecting means for counting said detected output, time measuring means coupled to said counting means for measuring a prescribed period of time after said counting means starts counting, and recording speed detecting means coupled to said counting means, said time measuring means and said transferring speed changing means for determining a recording speed of said recording medium based on an output of said time measuring means when said time measuring means measures said prescribed period of time, whereby a selection signal is supplied to said transferring speed selecting means.

Claim 2

An apparatus for reproducing a video signal using a rotatable head for reproducing including at least two heads which can be alternately changed over by means of a head changeover signal, from a magnetic recording medium in which four kinds of pilot signals are each sequentially recorded in each track in superposition on a video signal sequentially recorded in each recording track disposed adjacent to each other by a helical scan method, sequentially in each field either at relatively fast standard playing speed or at relatively slow long playing speed, comprising; transferring means for transferring said magnetic recording medium, transfer speed changing means coupled to said transferring means for changing a transfer speed of said magnetic recording medium to either the standard playing speed or the long playing speed so as to adapt the reproducing speed to the speed at which the video signal was recorded, reproduced pilot signal generating means coupled to said rotatable head for reproducing for extracting said pilot signals from the signal reproduced by said rotatable head for providing reproduced pilot signals, reference signal generating means for sequentially providing four types of reference signals having different frequencies in response to said head changeover signal of at least two heads, said four types of reference signal being selected in the frequencies equal to those of said four types of pilot signals, comparing signal generating means coupled to said reproduced pilot signal generating means and said reference signal generating means for mixing said reproduced pilot signal and said reference signal for providing a comparing signal for detecting the level of said beat signal, tracking signal generating means coupled to said comparing signal generating means for generating the tracking signal responsive to the comparing output of said comparing signal generating means, fundamental cycle detecting means coupled to said tracking signal generating means for detecting a fundamental cycle of a comparing signal provided by said generating means, counting means coupled to said fundamental cycle detecting means for counting said detected output, time measuring means coupled to said counting means for measuring a prescribed period of time after said counting means starts counting, and recording speed detecting means coupled to said counting means, said time measuring means and said transferring speed changing means for determining a recording speed of said recording medium based on an output of said time measuring means when said time measuring means measures said prescribed period of time, whereby a selection signal is supplied to said transferring speed selecting means.