The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 01, 1980
Filed:
Oct. 16, 1978
Sony Corporation, Tokyo, JP;
Abstract
In an automatic phase control circuit having a predetermined lock-in range wherein the oscillating signal produced by the adjustable oscillator of the automatic phase control circuit is used in combination with an input signal to derive a signal whose phase is compared to a reference signal, the phase difference between the derived signal and the reference signal being used as a phase control signal for the oscillator so as to minimize this phase difference and thus lock the phase of the derived signal to that of the reference signal, a method of adjusting the oscillator in the event that the phase relation between the oscillating signal and the input signal is outside the lock-in range. During recurrent intervals, which vary with time base errors in the input signal, the number of cycles of the oscillating signal is counted. The count is examined to determine whether it is within a predetermind range of a predetermined count, and if outside this range, the oscillating frequency of the oscillator is adjusted in a direction to return the count to within this predetermined range. In a preferred embodiment, this automatic phase control circuit is used to eliminate time-base errors in at least the chrominance signal of a composite color video signal. In such an embodiment, the adjustable oscillator is used in a frequency-converter for converting the frequency of at least the chrominance signal from an input frequency to a different frequency, and it is the phase of the frequency-converted chrominance signal which is compared to the reference signal.