US5574406A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase lock loop with error measurement and correction in alternate periods
Assignee: RCA Licensing Corp
•
Filing: 1994-04-19
•
Granted: 1996-11-12
•
Expires: 2014-04-19
Abstract
Abstract In a phase-lock-loop circuit a frequency detector measures a frequency error between an oscillatory signal and a synchronizing signal in alternate horizontal line periods for generating a frequency error indicative signal. The frequency error indicative signal is applied to an oscillator for correcting the frequency error in other alternate horizontal line periods in a manner to prevent frequency error measurement and correction from occurring in the same horizontal line period.
Inventors
- 👤 Donald J. Sauer
- 👤 William E. Rodda
- 👤 Edward R. Campbell, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:47
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/14; H03L7/099; H03L7/0991; H03L7/10; H03L7/113; H04; H04N; H04N7/00; H04N7/12; H04N7/122; H03B; H03B2201/00; H03B2201/02; H03B2201/025; H03B2201/0266; H03J; H03J2200/00; H03J2200/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
112 words
An apparatus for generating an oscillatory signal that is locked to a synchronizing signal, comprising: a source of said synchronizing signal at a frequency that is related to a horizontal scanning frequency; a controllable oscillator for generating said oscillatory signal; and a detector responsive to said oscillatory and synchronizing signals for measuring a cycle related error therebetween and for generating a signal that is indicative of said error, said error indicative signal being coupled to said oscillator for varying a cycle of said oscillatory signal when said error exceeds a first value, the variation of said cycle of said oscillatory signal and the measurement of said error occurring, alternately, in non-overlapping periods.
Claim 2
Independent Claim
112 words
An apparatus for generating an oscillatory signal that is locked to a synchronizing signal, comprising: a source of said synchronizing signal at a frequency that is related to a horizontal scanning frequency; a controllable oscillator for generating said oscillatory signal; and a detector responsive to said oscillatory and synchronizing signals for measuring a cycle related error therebetween and for generating a signal that is indicative of said error, said error indicative signal being coupled to said oscillator for varying a cycle of said oscillatory signal when said error exceeds a first value, the variation of said cycle of said oscillatory signal and the measurement of said error occurring, alternately, in non-overlapping periods.
Claim 3
Dependent Claim
36 words
An apparatus according to claim 1 wherein said detector comprises a frequency detector, wherein said cycle related error is a frequency error and wherein said frequency error indicative signal varies a frequency of said oscillatory signal.
Claim 4
Dependent Claim
25 words
An apparatus according to claim 2 wherein the variation of said oscillatory signal is prevented from occuring simultaneously with the measurement of said frequeny error.
Claim 5
Dependent Claim
54 words
An apparatus according to claim 3 wherein the frequency measurement occurs in each of a given pair of horizontal line periods and wherein the variation of said oscillatory signal occurs during an interval between said pair having a length that is equal to an integer multiple of a length of a horizontal line period.
Claim 6
Dependent Claim
60 words
An apparatus according to claim 3 further comprising, means for controlling said apparatus in a coarse frequency correction mode when said frequency error exceeds a second value that is larger than said first value and for controlling said apparatus in a fine frequency correction mode when said frequency error exceeds said first value and does not exceed said second value.
Claim 7
Dependent Claim
85 words
An apparatus according to claim 3 further comprising, a phase detector responsive to said oscillatory and synchronizing signals for measuring a phase error therebetween to generate a signal that is indicative of said phase error, said phase error indicative signal being coupled to a control input of said oscillator for varying a phase of said oscillatory signal when said frequency error does not exceed said first value, the variation of said phase of said oscillatory signal and the measurement of said phase error occurring simultaneously.
Claim 8
Dependent Claim
95 words
An apparatus according to claim 3 wherein said frequency detector comprises, means for measuring a ratio between a length of a period of said oscillatory signal and a length of a period of said synchronizing signal and for generating a signal that is indicative of said ratio, and means responsive to a signal that is indicative of an anticipated ratio between said length of said period of said oscillatory signal and said length of said period of said synchronizing signal for generating said frequency error indicative signal in accordance with a difference between said ratios.
References Cited (Backward Citations)
US4514705A
Cited
US4484152A
Cited
US4516118A
Cited
US4531102A
Cited
US4498059A
Cited
US4616259A
Cited
US4580107A
Cited
US4654604A
Cited
US4594564A
Cited
US4843332A
Cited
US4745372A
Cited
US4812783A
Cited
US4837781A
Cited
US4797634A
Cited
US4881048A
Cited
US4920322A
Cited
US4878231A
Cited
US4827225A
Cited
US4918405A
Cited
US4890071A
Cited
US4920320A
Cited
US4935706A
Cited
US4974081A
Cited
US5162910A
Cited
US5298870A
Cited
US5159292A
Cited
US5172076A
Cited
US5239274A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-11-12 | 2000-05-13 | 2000-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-12 | 2004-05-13 | 2004-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-12 | 2008-05-13 | 2008-11-12 | $7700.00 | Window Closed / Lapsed |