Video digital display device with analog input
AssigneeRCA Corporation
InventorFinis Claude Easter
Life of this patent
Estimating the term…
Abstract
An analog-to-digital converter includes a common input amplifying device such as a transistor in differential amplifier relationship with each of a plurality of output amplifying devices, one for each voltage range converted to digital form. Separately controllable circuits are provided for: (A) setting a video display screen signal to the threshold of visibility, and (B) increasing the brightness of the screen to various levels above the threshold in accordance with digital signals from the analog-to-digital converter as modified by a brightness control.
Claims13
An analog-to-digital converter responsive to an input signal from an input signal source which, as a function of time, varies over a range of values for producing time spaced discrete output signals in accordance with the value of said input signal within said range comprising in combination:
- a sole input amplifying device having an input terminal coupled to receive said input signal and an output terminal;
- a plurality, X, of resistive potential divider networks dividing by different factors, each having a pair of input terminals and an output terminal, one input terminal of which is coupled to said output terminal of said amplifying device;
- the other input terminal of which is coupled to a common source of potential;
- and
- a like plurality, X, of transistor means each having a principal conductive path between first and second electrodes, the conductivity of which is controlled responsive to potential appearing between said first electrode and a control electrode, said first electrode being connected to an output terminal of a respective one of said potential divider networks, said control electrodes being connected to a common source of potential, signals at said respective second electrodes being representative of different ranges within said range of values.
A video display device including a display screen responsive to an input signal at various values for correspondingly displaying related levels of brightness on related portions of the screen and which screen includes at least a portion which is dark comprising in combination:
- means normally setting said input signal to a value corresponding to a screen level below the threshold of visibility;
- means responsive to said input signal being at a value corresponding to any level of brightness on said screen for producing a first signal which will cause said screen to rise to the threshold of visibility;
- means responsive to said input signal being at a value corresponding to any level of brightness on said screen for producing a second signal which when additively mixed with said first signal causes said screen to exhibit a brightness level which level is a function of the value of said input signal;
- additive mixing means responsive to said first and second signals for summing said signals and for applying the summed signal to said display screen for causing appropriate portions of said screen to exhibit various levels of brightness only when an input signal corresponding to some brightness level is present, other portions of said screen being dark.
A video display device having an input terminal for receiving input signals thereat and in accordance with the value of said signals for displaying at various points on the screen of said device, various levels of brightness and responsive to one input signal value for displaying a dark screen comprising in combination:
- means coupled to receive said input signals and responsive to all input signal values except said one input signal value for supplying to said input terminal a first signal of magnitude such that said screen is driven to the threshold of visibility above which said screen exhibits perceptible brightness;
- means also coupled to receive said input signals and responsive to all input signal values except said one input signal value for supplying to said input terminal a signal which is a function of the value of said input signal, the magnitude of which when combined with said first signal causes said screen to exhibit various levels of brightness as a function of said input signal value.
Dependencies are inferred from the claim text.