US5706035A
Expired / Lapsed
US
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Display control apparatus
Assignee: Canon Inc
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Filing: 1994-04-28
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Granted: 1998-01-06
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Expires: 2014-04-28
Abstract
Abstract In a video display control, a phase locked loop (PLL) circuit generates a multiplied frequency signal from a reference signal. The stability of the PLL circuit is maintained even when the reference signal has different frequencies by providing a number of multiplication values corresponding to the number of different reference signal frequencies and switching the multiplication value when a change in frequency is detected to stabilize the PLL circuit.
Inventors
- 👤 Takashi Tsunoda
- 👤 Hideo Kanno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:18
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/003; G09G5/006; G09G5/008; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3622; G09G3/3629; G09G5/36; G09G5/363; G09G5/366; H; H03; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/18; G09G2310/00; G09G2310/04; G09G3/2007; G09G3/2059
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
116 words
A display control apparatus for generating a dot clock signal to display a video signal in response to a synchronous signal, said display control apparatus comprising: comparison means for comparing a synchronous signal with a divided signal; clock generation means for generating a dot clock signal for display according to results obtained by said comparison means; storage means for storing first and second values for alteration of said dot clock signal for display; divider means for generating said divided signal responsive to said stored values and said dot clock signal for display; and selection means for selecting the first or second value stored in said storage means in accordance with a change in the synchronous signal.
Claim 2
Dependent Claim
116 words
A display control apparatus for generating a dot clock signal to display a video signal in response to a synchronous signal, said display control apparatus comprising: comparison means for comparing a synchronous signal with a divided signal; clock generation means for generating a dot clock signal for display according to results obtained by said comparison means; storage means for storing first and second values for alteration of said dot clock signal for display; divider means for generating said divided signal responsive to said stored values and said dot clock signal for display; and selection means for selecting the first or second value stored in said storage means in accordance with a change in the synchronous signal.
Claim 3
Dependent Claim
26 words
A display control apparatus according to claim 1, wherein said synchronous signal comprises at least one of a horizontal synchronous signal and a vertical synchronous signal.
Claim 4
Dependent Claim
23 words
A display control apparatus according to claim 2, wherein said selection means selects in accordance with a change in said vertical synchronous signal.
Claim 5
Dependent Claim
90 words
A display control method for generating a dot clock signal in response to a synchronous signal to control a video display, comprising the steps of: comparing the synchronous signal with a divided signal; generating a dot clock signal for display responsive to a result of said comparison; storing first and second values for alteration of the dot clock signal; generating the divided signal responsive to the stored values and the dot clock signal; and selecting the stored first or second value in response to a change in the synchronous signal.
Claim 6
Dependent Claim
90 words
A display control method for generating a dot clock signal in response to a synchronous signal to control a video display, comprising the steps of: comparing the synchronous signal with a divided signal; generating a dot clock signal for display responsive to a result of said comparison; storing first and second values for alteration of the dot clock signal; generating the divided signal responsive to the stored values and the dot clock signal; and selecting the stored first or second value in response to a change in the synchronous signal.
Claim 7
Dependent Claim
141 words
An information processing apparatus comprising: receiving means for receiving an image signal and a synchronous signal which are provided from outside; comparison means for comparing the synchronous signal with a divided signal; clock generation means for generating a dot clock signal for display according to results obtained by said comparison means; storage means for storing first and second values for alteration of said dot clock signal for display; divider means for generating said divided signal responsive to said stored values and said dot clock signal for display; selection means for selecting the first or second value stored in said storage means in accordance with a change in the synchronous signal; sampling means for sampling said image signal based on said dot clock signal; and display control means for displaying an image signal sampled by said sampling means on a display device.
Claim 8
Dependent Claim
141 words
An information processing apparatus comprising: receiving means for receiving an image signal and a synchronous signal which are provided from outside; comparison means for comparing the synchronous signal with a divided signal; clock generation means for generating a dot clock signal for display according to results obtained by said comparison means; storage means for storing first and second values for alteration of said dot clock signal for display; divider means for generating said divided signal responsive to said stored values and said dot clock signal for display; selection means for selecting the first or second value stored in said storage means in accordance with a change in the synchronous signal; sampling means for sampling said image signal based on said dot clock signal; and display control means for displaying an image signal sampled by said sampling means on a display device.
Claim 9
Dependent Claim
19 words
The information processing apparatus according to claim 5, wherein the display device is a ferroelectric liquid crystal display device.
Claim 10
Dependent Claim
26 words
The information processing apparatus according to claim 5, wherein said synchronous signal comprises at least one of a horizontal synchronous signal and a vertical synchronous signal.
Claim 11
Dependent Claim
24 words
The information processing apparatus according to claim 7, wherein and said selection means selects in accordance with a change in said vertical synchronous signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-01-05 | 2001-07-07 | 2002-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-05 | 2005-07-07 | 2006-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-05 | 2009-07-07 | 2010-01-06 | $7700.00 | Window Closed / Lapsed |