US5281926A
Expired / Lapsed
US
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Phase locked loop made operative when stable input sync signal is detected
Assignee: LG Electronics Inc
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Filing: 1992-10-06
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Granted: 1994-01-25
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Expires: 2012-10-06
Abstract
Abstract An oscillator control system includes a phase-locked loop having a programmable frequency divider operative within the loop. A switch is further included within the phase-locked loop to permit the loop to be open or closed in response to an input signal. A counter accumulates oscillator clock signal counts between each successive rising edge portion of the applied sync signal. A pair of shift registers sequentially store successive clock signal counts for the current and previous sync signal intervals. The output counts are compared for consistency by producing a difference signal therebetween which is utilized to control the phase-locked loop switch and close it once the consistency of sync signal has been established. The output counts of the shift registers are combined and used to provide a scaling factor which sets the frequency division of the programmable frequency divider within the phase-locked loop and properly scales the oscillator frequency to the sync signal frequency.
Inventors
- 👤 Khosro M. Rabii
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:46
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/18; H03L7/197; H03L7/1972; H03L7/08; H03L7/14; H04; H04N; H04N5/00; H04N5/04; H04N5/12; H04N5/126
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
58 words
A method for controlling an oscillator signal in response to a sync signal comprising the steps of: establishing a succession of numeric counts representative of successive sync signal intervals; determining the consistency of successive numeric counts as a measure of sync signal consistency; and operating a phase lock loop upon said oscillator when sync signal consistency is established.
Claim 2
Independent Claim
58 words
A method for controlling an oscillator signal in response to a sync signal comprising the steps of: establishing a succession of numeric counts representative of successive sync signal intervals; determining the consistency of successive numeric counts as a measure of sync signal consistency; and operating a phase lock loop upon said oscillator when sync signal consistency is established.
Claim 3
Dependent Claim
27 words
The method of claim 1 further including the step of frequency dividing the output signal of said oscillator by a factor directly related to said numeric counts.
Claim 4
Dependent Claim
63 words
The method of claim 2 wherein said determining step includes the steps of: subtracting a selected numeric count from a numeric count preceding it to obtain a difference number; taking the absolute value of said difference number; comparing said absolute value to a reference number; and opening said phase-locked loop unless said absolute value is equal to or less than said reference number.
Claim 5
Dependent Claim
61 words
The method of claim 3 wherein said step of frequency dividing includes the steps of: adding said selected numeric count to said preceding numeric count to form a numeric sum; dividing said numeric sum by a fixed number to produce a scaling factor; and frequency dividing said oscillator signal during said step of operating said phase-locked loop by said scaling factor.
Claim 6
Dependent Claim
26 words
The method of claim 4 wherein said selected numeric count is the most recent count and said numeric count preceding it is the directly preceding count.
Claim 7
Dependent Claim
71 words
The method set forth in claim 1 wherein said step of operating a phase-locked loop includes the steps of: frequency dividing said oscillator signal by a scaling factor to produce a frequency divided oscillator signal; phase comparing said frequency divided oscillator signal to said sync signal to produce an error signal; coupling said error signal to said oscillator to control the frequency thereof only after sync signal consistency has been established.
Claim 8
Dependent Claim
63 words
The method of claim 6 wherein said determining step includes the steps of: subtracting a selected numeric count from a numeric count preceding it to obtain a difference number; taking the absolute value of said difference number; comparing said absolute value to a reference number; and opening said phase-locked loop unless said absolute value is equal to or less than said reference number.
Claim 9
Dependent Claim
61 words
The method of claim 7 wherein said step of frequency dividing includes the steps of: adding said selected numeric count to said preceding numeric count to form a numeric sum; dividing said numeric sum by a fixed number to produce a scaling factor; and frequency dividing said oscillator signal during said step of operating said phase-locked loop by said scaling factor.
Claim 10
Dependent Claim
26 words
The method of claim 8 wherein said selected numeric count is the most recent count and said numeric count preceding it is the directly preceding count.
Claim 11
Dependent Claim
63 words
For use in controlling an oscillator signal in response to a sync signal control means comprising: means for establishing a succession of numeric counts representative of successive sync signal intervals; means for determining the consistency of successive numeric counts as a measure of sync signal consistency; and means for operating a phase lock loop upon said oscillator when sync signal consistency is established.
Claim 12
Dependent Claim
63 words
For use in controlling an oscillator signal in response to a sync signal control means comprising: means for establishing a succession of numeric counts representative of successive sync signal intervals; means for determining the consistency of successive numeric counts as a measure of sync signal consistency; and means for operating a phase lock loop upon said oscillator when sync signal consistency is established.
Claim 13
Dependent Claim
29 words
Control means as set forth in claim 10 further including means for frequency dividing the output signal of said oscillator by a factor directly related to said numeric counts.
Claim 14
Dependent Claim
72 words
Control means as set forth in claim 11 wherein said means for determining includes: means for subtracting a selected numeric count from a numeric count preceding it to obtain a difference number; means for taking the absolute value of said difference number; means for comparing said absolute value to a reference number; and means for opening said phase-locked loop unless said absolute value is equal to or less than said reference number.
Claim 15
Dependent Claim
67 words
Control means a set forth in claim 12 wherein said means for frequency dividing includes: means for adding said selected numeric count to said preceding numeric count to form a numeric sum; means for dividing said numeric sum by a fixed number to produce a scaling factor; and means for frequency dividing said oscillator signal during said step of operating said phase-locked loop by said scaling factor.
Claim 16
Dependent Claim
29 words
Control means as set forth in claim 13 wherein said selected numeric count is the most recent count and said numeric count preceding it is the directly preceding count.
Claim 17
Dependent Claim
74 words
The method set forth in claim 10 wherein said means for operating a phase-locked loop includes: means for frequency dividing said oscillator signal by a scaling factor to produce a frequency divided oscillator signal; means for phase comparing said frequency divided oscillator signal to said sync signal to produce an error signal; means for coupling said error signal to said oscillator to control the frequency thereof only after sync signal consistency has been established.
Claim 18
Dependent Claim
72 words
Control means as set forth in claim 15 wherein said means for determining includes: means for subtracting a selected numeric count from a numeric count preceding it to obtain a difference number; means for taking the absolute value of said difference number; means for comparing said absolute value to a reference number; and means for opening said phase-locked loop unless said absolute value is equal to or less than said reference number.
Claim 19
Dependent Claim
67 words
Control means as set forth in claim 16 wherein said means for frequency dividing includes: means for adding said selected numeric count to said preceding numeric count to form a numeric sum; means for dividing said numeric sum by a fixed number to produce a scaling factor; and means for frequency dividing said oscillator signal during said step of operating said phase-locked loop by said scaling factor.
Claim 20
Dependent Claim
29 words
Control means as set forth in claim 17 wherein said selected numeric count is the most recent count and said numeric count preceding it is the directly preceding count.
References Cited (Backward Citations)
US5019907A
Cited
US5038116A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-01-24 | 1997-07-26 | 1998-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-24 | 2001-07-26 | 2002-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-24 | 2005-07-26 | 2006-01-25 | $7700.00 | Window Closed / Lapsed |