Synchronization method and apparatus for disc recorders

Claim 1

In a system for synchronizing a video source and a recording disc having prerecorded clock signals on a first track thereof, the combination of: master clock means for supplying master clock signals; sync generator means for supplying drive and synchronizing signals for controlling said video source and further supplying servo clock signals in response to said master clock signals; servo drive means for driving said disc at a predetermined speed in response to a comparison of said prerecorded clock signals and said servo clock signals; recording means for recording a predetermined quantity of said master clock signals on a second track of said disc; playback means for applying said recorded clock signals from said second track to said sync generator means rather than said master clock signals from said master clock means so that said drive and synchronizing signals for controlling said video source are generated in response thereto to synchronize directly thereto said disc and said video source; external means for supplying external clock signals to said servo drive means for comparison with said predetermined clock signals rather than said servo clock signals from said sync generation means to control the speed of said disc thereby, first switch means operative in a first position to apply said master clock signals to said sync generator means and in a second position to apply said recorded master clock signals to said sync generator means; and second switch means for applying said servo clock signals to said servo drive means when in a first position and to appLy said external clock signals to said servo drive means when in a second position.