US3678191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crt blanking and brightness control circuit
Assignee: National Aeronautics and Space Administration
•
Filing: 1968-11-12
•
Granted: 1972-07-18
•
Expires: 1988-11-12
Abstract
Abstract The disclosed embodiment of the present invention is a CRT blanking and brightness control circuit which employs an amplifier stage responsive to a square wave input signal and having an output connected to the cathode of a CRT, a wave shaping circuit connected to the load impedance of the amplifier stage, and a level control circuit connected to the output of the amplifier stage. The wave shaping circuit is responsive to the trailing edge of the input signal for discharging the stray capacitance associated with the load impedance to effect a fast rise time of the signal at the output of the amplifier stage. The level control circuit is operable to vary the amplitude of the amplifier stage output which is applied to the cathode of the CRT.
Inventors
- 👤 Robert L Peters
- 👤 Kenneth F Koch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:23
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/148; H04N3/00; H04N3/10; H04N3/16; H04N3/24
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
114 words
A switching circuit including an amplifier stage responsive to a relatively low amplitude square wave signal to develop a relatively large amplitude square wave signal, said amplifier stage having stray capacitance therein, the improvement therewith comprising; a. means connected to said amplifier stage for discharging the stray capacitance; b. means responsive to the low amplitude square wave signal and connected to said discharging means for actuating said discharging means; c. an amplitude control circuit including a voltage divider circuit having one end connected to the output of said amplifier stage; and d. means for applying a variable voltage connected to the other end of said voltage divider circuit for applying a variable voltage thereto.
Claim 2
Dependent Claim
114 words
A switching circuit including an amplifier stage responsive to a relatively low amplitude square wave signal to develop a relatively large amplitude square wave signal, said amplifier stage having stray capacitance therein, the improvement therewith comprising; a. means connected to said amplifier stage for discharging the stray capacitance; b. means responsive to the low amplitude square wave signal and connected to said discharging means for actuating said discharging means; c. an amplitude control circuit including a voltage divider circuit having one end connected to the output of said amplifier stage; and d. means for applying a variable voltage connected to the other end of said voltage divider circuit for applying a variable voltage thereto.
Claim 3
Dependent Claim
110 words
A CRT biasing circuit comprising: a. an amplifier stage including a load impedance connected to a source of voltage and having an input and an output; b. means connecting a square wave signal to the input of said amplifier stage; c. means connected between the source of voltage and the output of said amplifier stage for discharging any stray capacitance in response to a change from one amplitude level to another amplitude level of the square wave signal; d. a voltage divider circuit having one end connected to the output of said amplifier stage; and e. means connecting a variable voltage to the other end of said voltage divider circuit.
Claim 4
Dependent Claim
110 words
A CRT biasing circuit comprising: a. an amplifier stage including a load impedance connected to a source of voltage and having an input and an output; b. means connecting a square wave signal to the input of said amplifier stage; c. means connected between the source of voltage and the output of said amplifier stage for discharging any stray capacitance in response to a change from one amplitude level to another amplitude level of the square wave signal; d. a voltage divider circuit having one end connected to the output of said amplifier stage; and e. means connecting a variable voltage to the other end of said voltage divider circuit.
References Cited (Backward Citations)
US3071651A
Cited
US2997602A
Cited
US3005929A
Cited
US3157797A
Cited
US3171984A
Cited
US3307044A
Cited
US3459992A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |