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Patent US4598317A successfully refreshed from Google Patents.
US4598317A
Expired / Lapsed
US
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Ramp comparator arrangement useful in an on-screen channel indicator system of a television receiver
Assignee: RCA Licensing Corp
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Filing: 1984-01-23
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Granted: 1986-07-01
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Expires: 2004-01-23
Abstract
Abstract A television receiver includes a tuner responsive to a tuning voltage generated by a signal seeking tuning control unit and a channel indicator for displaying a vertical bar on the screen of the picture tube. The horizontal position of the bar is determined by the magnitude of the tuning voltage. The channel indicator includes a ramp signal generator for generating a composite ramp signal including a horizontal deflection rate ramp signal superimposed on the tuning voltage, a first AND function gate acting as a comparator to generate a first transition when the amplitude of the composite ramp signal traverses a switching threshold, a differentiator for determining the width of the bar having an input coupled to the output of the first AND function gate and an output coupled to a second AND gate which selectively couples the output signal of the differentiator to the picture tube when it is desired to display the bar. The two AND function gates are included in the same integrated circuit and, therefore, the output signal of the second AND function gate may be coupled to the first AND function gate to cause it to falsely switch thereby producing a disconcerting second bar on the screen. To overcome this problem, a feedback network is coupled between the output of the differentiator and a second input of the first AND gate to disable it from generating a second transition for a predetermined time after the first transition.
Inventors
- 👤 Ju M. Yu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:27
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/50
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
317 words
In a television receiver including tuner means controlled in response to a tuning signal generated by a tuning control unit for tuning RF signals corresponding to respective channels; signal processing means coupled to said tuner means for generating a picture representative baseband signal including picture synchronization components; deflection means responsive to said synchronization component for generating horizontal and vertical rate deflection signals; and an image producing device responsive to said picture representative signal and said horizontal and vertical rate deflection signals for producing an image; and an on-screen channel indicator apparatus, said on-screen channel indicator apparatus comprising: a ramp signal generator coupled to said deflection unit and to said tuning control means to generate a composite ramp signal including a ramp component varying at one of said deflection rates and a level component determined by said tuning signal; first and second logic gates, each having at least one input and an output, included in a single integrated circuit; said composite ramp signal being coupled to said input of said first logic gate, said first logic gate generating a first transition at its said output when the amplitude of said composite ramp signal traverses a predetermined switching threshold in a predetermined sense; pulse generating means having an input coupled to said output of said first logic gate and an output coupled to said input of said second logic gate for generating at said output of said second logic gate a pulse having a predetermined time duration in response to said first transition; coupling means for coupling said output of said second logic gate to said image reproducing device; and feedback means coupled between said output of said pulse generating means and said first logic gate and cooperating with said pulse generating means for inhibiting said first logic gate from generating a second transition at its said output for a predetermined time after the generation of said first transition.
Claim 2
Dependent Claim
317 words
In a television receiver including tuner means controlled in response to a tuning signal generated by a tuning control unit for tuning RF signals corresponding to respective channels; signal processing means coupled to said tuner means for generating a picture representative baseband signal including picture synchronization components; deflection means responsive to said synchronization component for generating horizontal and vertical rate deflection signals; and an image producing device responsive to said picture representative signal and said horizontal and vertical rate deflection signals for producing an image; and an on-screen channel indicator apparatus, said on-screen channel indicator apparatus comprising: a ramp signal generator coupled to said deflection unit and to said tuning control means to generate a composite ramp signal including a ramp component varying at one of said deflection rates and a level component determined by said tuning signal; first and second logic gates, each having at least one input and an output, included in a single integrated circuit; said composite ramp signal being coupled to said input of said first logic gate, said first logic gate generating a first transition at its said output when the amplitude of said composite ramp signal traverses a predetermined switching threshold in a predetermined sense; pulse generating means having an input coupled to said output of said first logic gate and an output coupled to said input of said second logic gate for generating at said output of said second logic gate a pulse having a predetermined time duration in response to said first transition; coupling means for coupling said output of said second logic gate to said image reproducing device; and feedback means coupled between said output of said pulse generating means and said first logic gate and cooperating with said pulse generating means for inhibiting said first logic gate from generating a second transition at its said output for a predetermined time after the generation of said first transition.
Claim 3
Dependent Claim
14 words
The apparatus recited in claim 1, wherein: said pulse generating means includes a differentiator.
Claim 4
Dependent Claim
58 words
9. The apparatus recited in claim 2, wherein: said first logic gate is an AND function gate having first and second inputs; said composite ramp signal is coupled to said first input of said first logic gate; and said feedback means is coupled between said output of said differentiator and said second input of said first logic gate.
Claim 5
Dependent Claim
46 words
The apparatus recited in claim 3, wherein: said feedback means is DC coupled between said output of said differentiator and said second input of said first logic gate and includes bias means for normally enabling said first logic gate to respond to said composite ramp signal.
Claim 6
Dependent Claim
29 words
The apparatus recited in claim 4, wherein: said feedback means includes a resistor coupled between said output of said differentiator and said second input of said first logic gate.
Claim 7
Dependent Claim
71 words
The apparatus recited in claim 5, wherein: said second logic gate is also an AND function gate having first and second inputs, said first input being coupled to said output of said differentiator; and said channel indicator apparatus further includes display enabling means coupled to said second input of said second logic gate for enabling said second logic element to respond to the signal produced at the output of said differentiator.
References Cited (Backward Citations)
US4204173A
Cited
US4366502A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-30 | 1989-12-30 | 1990-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-30 | 1993-12-30 | 1994-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-30 | 1997-12-30 | 1998-07-01 | $7700.00 | Window Closed / Lapsed |