Precision drive for video disc recorder using a free running or crystal controlled oscillator

Claim 2

In a video recorder having transducer means for recording and playback of a video signal, a magnetic recording media, means including a drive motor for moving said media past said transducer means and a controller for said motor, an input terminal for video signals to be recorded, circuit means connecting signals from said input terminal to said transducer means, a tachometer driven by said motor, a sync separator circuit connected to said input terminal and operative to separate synchronizing information from the input signal, a phase detector receiving signals from said tachometer and providing corrective drive signals to said motor controller; the improvement comprising a crystal controlled oscillator circuit, a free running oscillator circuit, control circuit means rEsponsive to presence of an input signal at said terminal and controlling said oscillator circuits to provide a first comparison input from said crystal controlled oscillator to said phase detector when no input signal is present at said terminal and to provide a second comparison input to said phase detector from said free running oscillator when an input signal is present at said terminal, and a control connection from said sync separator circuit to said free running oscillator to key it from sync information in the input video signal.

Claim 3

A video recorder as defined in claim 1, said media being a disc having a magnetizable surface, said transducer being mounted to follow at least one circuit path on said disc surface, and said controller operating said motor at a speed related to the video signal frequency to allow recording of a single frame in one circular path.

Claim 4

In a magnetic disc video recorder having a transducer for recording and playback of a video signal, a magnetic recording disc, a drive motor connected to rotate said disc past said transducer, a controller for said motor, an input terminal for video signals to be recorded, a gating circuit connected to control the application of signals from said input terminal to said transducer, a tachometer driven by said motor, a sync separator circuit connected to said input terminal and operative to separate synchronizing information from the input signal, a phase detector receiving feedback signals from said tachometer and providing corrective drive signals to said controller; the improvement comprising an oscillator circuit, a crystal adapted for connection to said oscillator circuit to establish its frequency, a circuit component substitutable for said crystal to make said oscillator circuit free running, control circuit means responsive to presence of an input signal at said terminal and controlling the correction of said crystal or said circuit component into said oscillator circuit to provide a first comparison input from a crystal controlled oscillator to said phase detector when no input signal is present at said terminal and to provide a second comparison input to said phase detector from a free running oscillator when an input signal is present at said terminal, and a control connection from said sync separator circuit to said oscillator circuit to key it from sync information in the input video signal when it is functioning as a free running oscillator.

Claim 5

In a magnetic disc video recorder having a transducer for recording and playback of a video signal, a magnetic recording disc, a drive motor connected to rotate said disc past said transducer, a controller for said motor, an input terminal for video signals to be recorded, a gating circuit connected to control the application of signals from said input terminal to said transducer, a tachometer driven by said motor, a sync separator circuit connected to said input terminal and operative to separate synchronizing information from the input signal, a phase detector receiving feedback signals from said tachometer and providing corrective drive signals to said controller; the improvement comprising an oscillator circuit, a crystal adapted for connection to said oscillator circuit to establish its frequency, a circuit component substitutable for said crystal to make said oscillator circuit free running, control circuit means responsive to presence of an input signal at said terminal and controlling the correction of said crystal or said circuit component into said oscillator circuit to provide a first comparison input from a crystal controlled oscillator to said phase detector when no input signal is present at said terminal and to provide a second comparison input to said phase detector from a free running oscillator when an input signal is present at said terminal, and a control connection from said sync separator circuit to said oscillator circuit to key it from sync information in the input video signal when it is functioning as a free running oscillator.

Claim 6

In a video recorder having transducer means for recording and playback of a video signal, a magnetic recording media, means including a drive motor and a motor controller for moving said media past said transducer means at a predetermined speed, an input terminal for video signals to be recorded, a gating circuit connected to control the application of signals from said input terminal to said transducer means, a tachometer driven by said motor, a sync separator circuit connected to said input terminal and operative to separate synchronizing information from the input signal, and a phase detector receiving signals from said tachometer and providing corrective drive signals to said motor controller; the improvement comprising an oscillator circuit switchable between free running and fixed frequency modes, a control connection from said sync separator circuit to said oscillator circuit to key it from sync information in the input video signal, and control circuit means responsive to presence of an input signal at said terminal and controlling the operating mode of said oscillator circuit to provide a fixed frequency input from said oscillator circuit to said phase detector when no input signal is present at said terminal or to provide a comparison input to said phase detector from said oscillator circuit as keyed from the sync information in any input signal present at said terminal.

Claim 7

In a video recorder having transducer means for recording and playback of a video signal, a magnetic recording media, means including a drive motor and a motor controller for moving said media past said transducer means at a predetermined speed, an input terminal for video signals to be recorded, a gating circuit connected to control the application of signals from said input terminal to said transducer means, a tachometer driven by said motor, a sync separator circuit connected to said input terminal and operative to separate synchronizing information from the input signal, and a phase detector receiving signals from said tachometer and providing corrective drive signals to said motor controller; the improvement comprising an oscillator circuit switchable between free running and fixed frequency modes, a control connection from said sync separator circuit to said oscillator circuit to key it from sync information in the input video signal, and control circuit means responsive to presence of an input signal at said terminal and controlling the operating mode of said oscillator circuit to provide a fixed frequency input from said oscillator circuit to said phase detector when no input signal is present at said terminal or to provide a comparison input to said phase detector from said oscillator circuit as keyed from the sync information in any input signal present at said terminal.