US3718832A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for producing ramp signals and an intensity control signal in response to digital data, particularly for a crt vector generator
Assignee: INFORMATION DISPLAYS Inc
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Filing: 1970-08-21
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Granted: 1973-02-27
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Expires: 1990-08-21
Abstract
Abstract A vector generator is described operating on a constant writing speed basis for larger vectors and on a constant time basis for small vectors. The generator utilizes X,Y. Delta X, Delta Y and Delta Max digital data, Delta Max being the greater in magnitude of Delta X and Delta Y. A feedback control amplifier supplied with a constant input signal has two feedback loops. One loop includes a D/A attenuator supplied with Delta Max and the other includes a bias source which limits the output to a predetermined value for small values of Delta Max. The output of the D/A attenuator is used to produce an intensity control signal which varies with vector length in the region where limiting takes place. The control amplifier output is fed to a difference amplifier having a transistor-controlled feedback circuit to produce a current accurately proportional to the control amplifier output, and another transistor having an input circuit like that of the feedback transistor and supplied with the same input supplies charging current to a ramp capacitor. The ramp signal is compared with a reference to produce a ramp stop signal. Ramp start and stop signals are delayed and gate the intensity control signal, and the delayed stop signal is used to terminate the ramp rise. The ramp signals are supplied to D/A amplifiers controlled by the Delta X and Delta Y digital data to produce CRT deflection waves.
Inventors
- 👤 B Premru
- 👤 J Nash
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:57
CPC Classifications
G; G09; G09G; G09G1/00; G09G1/06; G09G1/08; H; H03; H03K; H03K4/00; H03K4/06; H03K4/08; H03K4/48; H03K4/50; H03K4/501
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
175 words
Apparatus for producing constant-amplitude variable-slope ramp signals and an intensity control signal in response to digital data which comprises a. an amplifier, b. input means for supplying a signal of constant value to the input of said amplifier, c. a feedback circuit for said amplifier including a digital-toanalog attenuator responsive to said digital data to produce a feedback signal to the input of the amplifier which is proportional to a fraction of the amplifier output signal whereby the amplifier output increases as said fraction decreases, d. limiting means for limiting said amplifier output to a predetermined value for small fractional outputs of said attenuator, e. ramp generator means for utilizing the output of said amplifier to produce ramp signals having slopes varying in accordance with the amplifier output, f. comparator means for comparing said ramp signals with a reference to produce signals for terminating the ramp signals, g. and means for utilizing the output of said digital-to-analog attenuator to produce an intensity control signal varying with the attenuator output in the region of said limiting.
Claim 2
Dependent Claim
175 words
Apparatus for producing constant-amplitude variable-slope ramp signals and an intensity control signal in response to digital data which comprises a. an amplifier, b. input means for supplying a signal of constant value to the input of said amplifier, c. a feedback circuit for said amplifier including a digital-toanalog attenuator responsive to said digital data to produce a feedback signal to the input of the amplifier which is proportional to a fraction of the amplifier output signal whereby the amplifier output increases as said fraction decreases, d. limiting means for limiting said amplifier output to a predetermined value for small fractional outputs of said attenuator, e. ramp generator means for utilizing the output of said amplifier to produce ramp signals having slopes varying in accordance with the amplifier output, f. comparator means for comparing said ramp signals with a reference to produce signals for terminating the ramp signals, g. and means for utilizing the output of said digital-to-analog attenuator to produce an intensity control signal varying with the attenuator output in the region of said limiting.
Claim 3
Dependent Claim
56 words
Apparatus in accordance with claim 1 in which said limiting means is a feedback circuit from the output to the input of said amplifier which includes a bias source in opposition to the amplifier output for preventing feedback when the output is below a predetermined value and allowing feedback when the output reaches said predetermined value.
Claim 4
Dependent Claim
82 words
Apparatus in accordance with claim 1 in which said amplifier is an operational amplifier, said input means includes a source of voltage and a series input resistor, said feedback circuit includes a series resistor between said attenuator and the amplifier input, and said limiting means is a feedback circuit from the output to the input of the amplifier which includes a series Zener diode and series blocking diode allowing feedback when the amplifier output reaches a predetermined value and preventing feedback therebelow.
Claim 5
Dependent Claim
145 words
Apparatus in accordance with claim 1 in which said ramp generator means includes a. first and second transistors connectEd as a differential amplifier, b. said amplifier output being supplied to the input of said first transistor, c. third and fourth transistors having like characteristics and like base-emitter input circuits and each having a collector output circuit, d. means for supplying the output of said first transistor to the input circuits of said third and fourth transistors, e. means for supplying the output of said third transistor to the input of said second transistor to form a feedback circuit whereby the collector output currents of the third and fourth transistors are each proportional to the input signal to the first transistor, f. a ramp capacitor, g. and means for supplying the output of said fourth transistor to said ramp capacitor to produce a ramp signal thereacross.
Claim 6
Dependent Claim
87 words
Apparatus in accordance with claim 4 in which said inputs to the first and second transistors are to the bases thereof and said output of the first transistor is from the collector thereof, said first and second transistors having a common emitter circuit including an emitter series resistance and a source of emitter bias predetermined to yield an incremental current change in said emitter series resistance which is substantially twice the incremental collector current change in said first transistor over the input range of the first transistor.
Claim 7
Dependent Claim
116 words
Apparatus in accordance with claim 1 utilizing initiating signals for initiating said ramp signals, and including a. switch means responsive to said initiating signals and to said signals from the comparator means for producing alternative start and stop signals, b. means for supplying said start signals to said ramp generator means for controlling the initiation of said ramp signals, c. delay means supplied with said start and stop signals for producing delayed start and delayed stop signals, d. means for supplying said delayed stop signals to said ramp generator means for controlling the stopping of said ramp signals, e. and means for utilizing said delayed start and delayed stop signals for gating said intensity control signal.
Claim 8
Dependent Claim
187 words
Apparatus in accordance with claim 4 utilizing initiating signals for initiating said ramp signals and in which said ramp capacitor and the emitter-collector circuit of said fourth transistor forms a series circuit, and including a. a discharge circuit for said ramp capacitor, b. a fifth transistor having an emitter-collector circuit connected in shunt with said series circuit for alternately turning said fourth transistor on and off when the fifth transistor is respectively off and on, c. switch means responsive to said initiating signals and to said signals from the comparator means for producing alternative start and stop signals, d. means for supplying said start signals to said discharge circuit and said fifth transistor to disable the discharge circuit and turn the fifth transistor off, e. delay means supplied with said start and stop signals for producing delayed start and delayed stop signals, f. means for supplying said delayed stop signals to said discharge circuit and said fifth transistor to enable the discharge circuit and turn the fifth transistor on, g. and means for utilizing said delayed start and delayed stop signals for gating said intensity control signal.
Claim 9
Dependent Claim
117 words
Apparatus in accordance with claim 1 for producing deflection and intensity control signals to draw vectors on a cathode-ray tube display including a. a digital data source for supplying Delta X and Delta Y digital data for a vector and Delta Max digital data corresponding to the greater in magnitude of Delta X and Delta Y, b. said Delta Max digital data being supplied to said digital-to-analog attenuator, c. means for utilizing said ramp signals and said Delta X and Delta Y digital data to produce respective Delta X and Delta Y deflection signals for said cathode-ray tube display, d. and means for utilizinG said intensity control signal to control the intensity of said cathode-ray tube display.
Claim 10
Dependent Claim
83 words
Apparatus in accordance with claim 8 in which said amplifier is an operational amplifier, said input means includes a source of voltage and a series input resistor, said feedback circuit includes a series resistor between said attenuator and the amplifier input, and said limiting means is a feedback circuit from the output to the input of the amplifier which includes a series biased Zener diode and series blocking diode allowing feedback when the amplifier output reaches a predetermined value and preventing feedback therebelow.
Claim 11
Dependent Claim
144 words
Apparatus in accordance with claim 9 in which said ramp generator means includes a. first and second transistors connected as differential amplifier, b. said amplifier output being supplied to the input of said first transistor, c. third and fourth transistors having like characteristics and like base-emitter input circuits and each having a collector output circuit, d. means for supplying the output of said first transistor to the input circuits of said third and fourth transistors, e. means for supplying the output of said third transistor to the input of said second transistor to form a feedback circuit whereby the collector output currents of the third and fourth transistors are each proportional to the input signal to the first transistor, f. a ramp capacitor, g. and means for supplying the output of said fourth transistor to said ramp capacitor to produce a ramp signal thereacross.
Claim 12
Dependent Claim
87 words
Apparatus in accordance with claim 10 in which said inputs to the first and second transistors are to the bases thereof and said output of the first transistor is from the collector thereof, said first and second transistors having a common emitter circuit including an emitter series resistance and a source of emitter bias predetermined to yield an incremental current change in said emitter series resistance which is substantially twice the incremental collector current change in said first transistor over the input range of the first transistor.
Claim 13
Dependent Claim
116 words
Apparatus in accordance with claim 8 utilizing initiating signals for initiating said ramp signals, and including a. switch means responsive to said initiating signals and to said signals from the comparator means for producing alternative start and stop signals, b. means for supplying said start signals to said ramp generator means for controlling the initiation of said ramp signals, c. delay means supplied with said start and stop signals for producing delayed start and delayed stop signals, d. means for supplying said delayed stop signals to said ramp generator means for controlling the stopping of said ramp signals, e. and means for utilizing said delayed start and delayed stop signals for gating said intensity control signal.
Claim 14
Dependent Claim
187 words
Apparatus in accordance with claim 10 utilizing initiating signals for initiating said ramp signals and in which said ramp capacitor and the emitter-collector circuit of said fourth transistor forms a series circuit, and including a. a discharge circuit for said ramp capacitor, b. a fifth transistor having an emitter-collector circuit connected in shunt with said series circuit for alternately turning said fourth transistor on and off when the fifth transistor is respectively off and on, c. switch means responsive to said initiating signals and to said signals from the comparator means for producing alternative start and stop signals, d. means for supplying said start signals to said discharge circuit and said fifth transistor to disable the discharge circuit and turn the fifth transistor off, e. delay means supplied with said start and stop signals for producing delayed start and delayed stop signals, f. means for supplying said delayed stop signals to said discharge circuit and said fifth transistor to enable the discharge circuit and turn the fifth transistor on, g. and means foR utilizing said delayed start and delayed stop signals for gating said intensity control signal.
References Cited (Backward Citations)
US3544835A
Cited
US3588871A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |