Time base error signal generating apparatus

Claim 1

A time base error signal generating apparatus for detecting an error of a time base of a reproduced video signal containing a first playback sync signal (Pb-H) of a predetermined period and a second playback sync signal (Pb-V) of a longer period than the predetermined period and generating a time base error signal, the apparatus comprising phase comparing means (5) for detecting a phase difference between the first playback sync signal (b) and a first reference sync signal (a); characterised by: detecting means (7,9,10) for detecting a status of the phase of the second playback sync signal (d) with respect to a second reference sync signal (c), and generating a first control signal (k), in case of an advanced phase, for a duration according to the degree of the advancement, and generating a second control signal (1), in case of a delayed phase, for a duration according to the degree of the delay; and gate means (2,4) for inhibiting supply of the first reference sync signal (a) to the phase comparing means (5) in response to the first control signal (k) for the duration thereof, and inhibiting supply of the first playback sync signal (b) to the phase comparing means (5) in response to the second control signal (1) for the duration thereof, whereby the phase difference signal (o) from the phase comparing means (5) is output as the time base error signal.