Patent US3552545A successfully refreshed from Google Patents.
Patent EP0090426A2 successfully refreshed from Google Patents.
EP0090426A2
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EP
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Method and apparatus for measuring horizontal sync subcarrier phase
Assignee: Grass Valley Group Inc
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Filing: 1983-03-30
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Granted: —
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Expires: 2003-03-30
Abstract
Abstract The 50% point of the leading edge of sync is used to acquire the value of a color burst locked CW carrier, and a quadrature color burst locked CW carrier. The acquired value of each of the two carriers are split into two values representing the value on alternating horizontal lines. This requires the generation of a one-half horizontal rate signal (H/2) which can have an arbitrary phase relationship. The H/2 phase is associated with each of the four acquired CW carrier values and that information is used by a computing device. The H/2 signal is also used to gate a 30 Hz vertical frame pulse to generate a 15 HzV1 color frame pulse. The computing device receives the color frame pulse and records the time the pulse occurs. This information represents the minimum and sufficient set of data to obtain a complete measure of sync to subcarrier phase (SC/H) and color frame comparison. By multiplexing the acquisition electronics between two video sources, SC/H and color frame comparisons can be made by the computing device.
Inventors
- 👤 James Allen Michener
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 10:32
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/44; H04N9/455; H04N17/00; H04N17/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
170 words
A method for measuring horizontal sync to subcarrier phase of a video signal comprising the steps of: (a) receiving a sync window signal from the video signal having the sync pulses of the video signal inhibited for a period greater than one-half the horizontal sync period and less than the horizontal sync period; (b) generating two complementary signals each having a period substantially equal to twice the horizontal sync period in response to the signal received in step (a); (c) receiving a cw carrier signal having its phase locked to the burst of the video signal; (d) generating four sampled sine wave signals in quadrature phase, each having the same frequency as the subcarrier, from the signals of steps (a), (b), and (c); (e) measuring the value of each of the four sine wave signals of step (d) at the occurrence of the leading edge of the sync window signal of step (a); and (f) calculating the horizontal sync to subcarrier phase from the four measured values of step (e).
Claim 2
Independent Claim
170 words
A method for measuring horizontal sync to subcarrier phase of a video signal comprising the steps of: (a) receiving a sync window signal from the video signal having the sync pulses of the video signal inhibited for a period greater than one-half the horizontal sync period and less than the horizontal sync period; (b) generating two complementary signals each having a period substantially equal to twice the horizontal sync period in response to the signal received in step (a); (c) receiving a cw carrier signal having its phase locked to the burst of the video signal; (d) generating four sampled sine wave signals in quadrature phase, each having the same frequency as the subcarrier, from the signals of steps (a), (b), and (c); (e) measuring the value of each of the four sine wave signals of step (d) at the occurrence of the leading edge of the sync window signal of step (a); and (f) calculating the horizontal sync to subcarrier phase from the four measured values of step (e).
Claim 3
Dependent Claim
155 words
A method according to claim 1 wherein step (f) includes the steps of: (f) (i) determining the average peak value of the four sampled wave signals of step (d); (f)(ii) selecting the phase of one of the four sine wave signals of step (d) as the reference phase; (f)(iii) determining the quadrant in which the values of step (e) occur with relation to the selected phase relationship of step (f) (iii); (f)(iv) determining the phase relationship of the leading edge of the sync window signal to the nearest zero crossing of the four sine wave signals of step (d) in the quadrant determined in step (f)(iii) in response to the four measured values of step (e) and the value of step (f)(i); and (f) (v) adjusting the phase value of step (f)(iv) for the quadrant identified in step (f)(iii) to provide a measure of the phase lag from the reference phase selected in step (f)(ii).
Claim 4
Dependent Claim
84 words
A method acccording to claim 2 futher comprising receiving a color frame reference pulse of the video signal, measuring the time of receipt of the color frame reference against a selected free-running clock and storing the measured value, measuring the time of receipt of a color frame pulse from an independent source against the free-running clock and storing the measured value, comparing the stored measured values, and correcting the phase value of step (f)(v) by 180° when the compared measured values are substantially different.
Claim 5
Dependent Claim
56 words
A method according to claim 1 further comprising the steps of: (g) detecting the minimum and maximum values of step (f) phase values generated by repeating steps (a) through (f) a selected number of times; and (h) generating the sync to subcarrier time base error by taking the difference between the values detected in step (g).
Claim 6
Dependent Claim
59 words
A method according to claim 1, wherein step (b) includes the steps of: (b)(i) dividing the frequency of the signal of step (a) by two; (b)(ii) generating a square wave signal of arbitrary phase to the subcarrier in response to the signal of step (b)(i); and (b)(iii) generating a complementary signal to the signal of step (b) (ii) .
Claim 7
Dependent Claim
103 words
A method according to claim 1, 2 or 5, wherein step (c) includes the steps of: (c)(i) receiving a continuous wave carrier signal phase locked to the burst of the video signal; (c)(ii) delaying the signal of step (c)(i) by 9 00; (c)(iii) tracking each of the signals of steps (c)(i) and (c)(ii), and holding the value of each at the occurrence of the leading edge of the signal of step (a); and (c)(iv) sampling each of the signals of step (c)(iii) and holding the value of each at the occurrence of the leading edge of each of the signals of step (b).
Claim 8
Independent Claim
164 words
An apparatus for measuring horizontal sync to subcarrier phase of a video signal comprising: first means for receiving a sync window signal of the video signal having the sync pulses of the video signal inhibited for a period greater than one-half the horizontal sync period and less than the horizontal sync period; second means coupled to said first means for generating two complementary signals each having a period substantially equal to twice the horizontal sync period; third means for receiving a cw carrier signal having its phase locked to the burst of the video signal fourth means coupled to the first, second and third means for generating four sampled sine wave signals in quadrature phase, each having the same frequency as the subcarrier; fifth means for measuring the value of each of the four sine wave signals at the occurrence of the leading edge of the sync window signal; calculation means coupled to said fifth means for calculating the horizontal sync to subcarrier phase.
Claim 9
Independent Claim
164 words
An apparatus for measuring horizontal sync to subcarrier phase of a video signal comprising: first means for receiving a sync window signal of the video signal having the sync pulses of the video signal inhibited for a period greater than one-half the horizontal sync period and less than the horizontal sync period; second means coupled to said first means for generating two complementary signals each having a period substantially equal to twice the horizontal sync period; third means for receiving a cw carrier signal having its phase locked to the burst of the video signal fourth means coupled to the first, second and third means for generating four sampled sine wave signals in quadrature phase, each having the same frequency as the subcarrier; fifth means for measuring the value of each of the four sine wave signals at the occurrence of the leading edge of the sync window signal; calculation means coupled to said fifth means for calculating the horizontal sync to subcarrier phase.
References Cited (Backward Citations)
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