Method and apparatus for providing a timing signal with high frequency accuracy in video equipment for supporting an on-screen display in the absence of a video signal

A method of producing a clock signal for video reconstruction and an on-screen display in the absence of an incoming video signal, the method comprising:

• retrieving previously recorded control data for a voltage controlled oscillator which was output by a control logic circuit with a phase locked loop and recorded when said phase locked loop was locked to a clock signal component within an incoming video signal;
• outputting said control data to said voltage controlled oscillator to generate a clock signal for video reconstruction;
• and
• providing an on-screen display using said clock signal in the absence of an incoming video signal.

A system for generating an on-screen display in the absence of an incoming video signal comprising:

• means for receiving an incoming video signal and phase locking to a clock signal component within said incoming video signal, wherein said means for receiving an incoming video signal outputs a control signal based on said phase lock to control an output of a means for generating a clock signal;
• and
• means for recording control data of said control signal during said phase lock;
• wherein said recorded control data is used to control said means for generating a clock signal in the absence of an incoming video signal;
• and
• means for generating an on-screen display based on said clock signal.

A clock circuit for outputting a clock signal for video reconstruction in the absence of an incoming video signal comprising:

• a voltage controlled oscillator for outputting a clock signal;
• a control logic circuit for outputting a control signal to control said voltage controlled oscillator, wherein said control logic circuit compares said clock signal with a reference clock signal and adjusts said control signal in accordance with said comparison;
• and
• a circuit for recording control data of said control signal during said comparison;
• wherein said recorded control data is used by said clock circuit to control said voltage controlled oscillator to generate an on-screen display in the absence of said incoming video signal.

A clock circuit for outputting a clock signal for video reconstruction in the absence of an incoming video signal comprising:

• a voltage controlled oscillator for outputting a clock signal;
• a control logic circuit for outputting a control signal to control said voltage controlled oscillator, wherein said control logic circuit compares said clock signal with a reference clock signal and adjusts said control signal in accordance with said comparison;
• and
• a circuit for recording control data of said control signal during said comparison and for outputting said recorded control data to control said voltage controlled oscillator to generate an on-screen display in the absence of said incoming video signal.

A clock circuit for outputting a clock signal for video reconstruction in the absence of an incoming video signal comprising:

• a control logic circuit for receiving an incoming video signal, said control logic circuit comprising a phase locked loop circuit for phase locking to a clock signal component within said incoming video signal, wherein said control logic circuit outputs a control signal to control a voltage controlled oscillator based on said phase lock;
• and
• a circuit for recording control data of said control signal during said phase lock, said circuit for recording control data comprising a processor and a memory unit, wherein said memory unit is not continually refreshed during said phase lock;
• wherein said recorded control data is used by said clock circuit to control said voltage controlled oscillator in the absence of an incoming video signal.

A clock circuit for outputting a clock signal for video reconstruction in the absence of an incoming video signal comprising:

• a control logic circuit for receiving an incoming video signal, said control logic circuit comprising a phase locked loop circuit for phase locking to a clock signal component within said incoming video signal, wherein said control logic circuit outputs a digital control signal to control a voltage controlled oscillator based on said phase lock;
• and
• a circuit for recording control data of said digital control signal during said phase lock, said circuit for recording control data comprising a processor and a digital memory unit;
• wherein said recorded control data is used by said clock circuit to control said voltage controlled oscillator in the absence of an incoming video signal.