Self-tracking injection lock voltage controlled oscillator
AssigneeInternational Video Corporation
InventorsNikola Vidovic, Barrett E. Guisinger
Life of this patent
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Abstract
Apparatus, including an injection lock and voltage controlled oscillator, generates a signal that follows the average frequency variations and instantaneous phase variations of a repetitive non-continuous signal. The oscillator injection lock input receives the repetitive signal and its DC control input receives an error signal generated in an AFC loop which derives the difference between the oscillator output and the repetitive signal average frequency. In one particular application, the appartus is useful in a color television signal processing or reproducing system for generating a television color subcarrier signal. The apparatus is further disclosed in connection with a demodulation-remodulation type color corrector in a video reproducing system.
Claims8
Apparatus for generating a signal that follows the frequency and phase variations of a repetitive non-continuous signal comprising
- injection lock and voltage controlled oscillator means for generating an oscillator output signal having a phase responsive substantially instantaneously to the phase of an applied injection lock signal and a frequency responsive to an applied DC control signal,
- means for generating a siganl corresponding to the average frequency of said repetitive non-continuous signal,
- automatic frequency control loop means receiving said average frequency signal and said oscillator output signal for generating an error signal corresponding to the difference in frequency between said average frequency signal and said oscillator output signal and for applying said error signal to said oscillator means as the applied DC control signal, and
- means for applying said non-continuous signal to said oscillator means as the applied injection lock signal.
In a color television signal reproducing system wherein a reproduced composite color television signal is processed, apparatus for generating a television color subcarrier signal that follows the frequency and phase variations of a repetitive non-continuous television color burst signal of said composite color television signal comprising
- injection lock and voltage controlled oscillator means for generating said color subcarrier signal having a phase locking to the phase of an applied injection lock signal within the time period of said color burst and a frequency responsive to an applied DC control signal,
- means for generating a signal corresponding to the average frequency of said color burst signal,
- automatic frequency control loop means receiving said color burst average frequency signal and said color subcarrier signal for generating an error signal corresponding to the difference in frequency between said color burst average frequency signal and said color subcarrier signal and for applying said error signal to said oscillator means as the applied DC control signal, and
- means for applying said color burst signal to said oscillator means as the applied injection lock signal.
In a color television signal reproducing system wherein a reproduced composite color television signal is processed, apparatus for stabilizing the chroma portion of said reproduced composite color television signal comprising
- injection lock and voltage controlled oscillator means for generating a color subcarrier signal having a phase locking to the phase of an applied injection lock signal within the time period of said color burst and a frequency responsive to an applied DC control signal,
- means for generating a signal corresponding to the average frequency of the reproduced composite color television signal color burst,
- automatic frequency control loop means receiving said color burst average frequency signal and said color subcarrier signal for generating an error signal corresponding to the difference in frequency between said color burst average frequency signal and color subcarrier signal and for applying said error signal to said oscillator means as the applied DC control signal,
- demodulator means receiving said color subcarrier signal and the reproduced composite color television signal chroma portion for providing the demodulated color information in said reproduced composite color television signal chroma portion,
- means for generating a stable color subcarrier signal, and
- remodulator means receiving said demodulated color information and said stable color subcarrier signal for generating a stabilized composite color television signal chroma portion.
Dependencies are inferred from the claim text.