Abstract: A multilevel video display control circuit. A plurality of current levels are developed in response to coded command signals (P1, P2, P3). The generated currents are summed together and converted to analog voltage signals (V25) to control the brightness of the pixels on the display. A contrast adjustment network (26) includes a first potentiometer (K1) for setting the magnitude of one of the currents at a desired level. A second potentiometer (K2) is provided for varying the magnitudes of the other current levels while maintaining the first current at the preset magnitude. Preferably, the magnitude of the first current is inversely varied with respect to other current levels.

Abstract: A suppression circuit processes the video signal from an anti-comet tail (ACT) image pickup tube and develops a control signal indicative of illumination highlights exceeding a predetermined level. The control signal is coupled through ACT pulsing circuits to the control elements of the ACT image pickup tube to automatically enable the beam control element pulsing so as to increase the beam current only in the presence of an illumination highlight to force the recharging of the target to cathode potential in the area of the highlight.

Abstract: A color displaying method comprises determining the CIE (Commission Internationale d'Eclairage) tristimulus values of a desired color to be displayed. The tristimulus values are converted into corresponding electrical signals in accordance with the relative luminance value of the source of radiations employed to produce the desired color. A system for displaying colors is also disclosed which includes an electro-optical color imaging device. The tristimulus values of the desired color are generated in a computer in response to a set of numerical data keyed through a data input device. The tristimulus values are converted into corresponding electrical signals which are then corrected in amplitude in accordance with the emission characteristics of the imaging device. The latter is driven in response to the amplitude-corrected electrical signals to produce the desired color.

Abstract: A system for correcting for intensity variations and electron beam landing errors in a flat panel display device includes two compensation means. The first compensation means applies a continuously varying voltage to the modulation electrodes to add a varying current to the electron beam current. The compensation current offsets the intensity variations of the electron beam. The second compensation means applies an averaged position signal to the modulation electrodes to compensate for beam landing errors of the electron beam.

Abstract: A stabilization network is disclosed which compensates for variable emission characteristics of a cathode in a television receiver's cathode ray tube. During the receiver's vertical interval, a variable gain video amplifier applies a black level D.C. voltage to the cathode. The resulting cathode current is sensed and compared to a low level reference current. If the cathode current does not equal the reference current, a control signal is applied to the amplifier. The amplifier responds to changing its D.C. output voltage until the cathode current is equal to the reference current. The amplifier also responds to the control signal by altering its gain so that, when a video signal is received, the cathode develops peak white currents of a given value in response to peak white portions of the video signal.

Abstract: The minimum output level of an electron gun driven at discrete voltage levels is precisely established. A target value slightly above the minimum voltage level is compared with the actual value. The result of the comparison is used to uniformily establish the minimum electron gun drive voltage and thus compensates for electron gun transfer characteristic differences and variations within the gun drive circuitry. An additional circuit utilizing a target value slightly below the maximum voltage can be used to establish the maximum output level of the electron gun.

Abstract: A field emission gun, for either electron or positive ion emission, in which the beam current between source and sample is measured at accelerating voltage potential between two concentric shields that enclose the gun, its power supplies, and the measuring circuitry. The outer shield is directly connected to the high voltage terminal of the accelerating voltage supply while the inner shield is at the local ground reference of the emission source and associated components. The current between the concentric shields is measured, converted to a proportional voltage signal, compared with the reference voltage, and applied to a field strength controlling electrode in the vicinity of the emission source to modulate the emission and to maintain a constant beam current.

Abstract: In an image pick-up tube of the type having a cathode electrode which emits a scanning electron beam, a control electrode which regulates the current of the electron beam at the cathode electrode and through which there is a control electrode current flow during operation of the tube, and a target electrode from which a video output current signal is obtained in correspondence to incident light from an object image projected on the target electrode as the latter is scanned by the electron beam, apparatus for controlling the electron beam in the image pick-up tube includes a resistive circuit for generating a beam control voltage signal from the video output current signal, a circuit for supplying the beam control voltage signal to the control electrode for regulating the current of the electron beam at the cathode electrode, and a resistive element responsive to the control electrode current for imparting a non-linear characteristic to the beam control voltage signal for varying levels of the incident light t

Abstract: A beam amount of a diode gun type pick-up tube is controlled in response to an incident light amount. Such beam control is carried out by making an excess beam amount constant. The calculation of the excess beam amount is done by subtracting a control electrode current and a signal current from a cathode current in case of the diode gun type pick-up tube.

Abstract: In a flat panel cathodoluminescent display utilizing a plurality of electron guns a single line cathode is used as the electron source for all guns. Changes in electron beam current resulting from vibration of the line cathode are compensated for by the application of voltages which are related to the current changes. The compensating voltages are applied through an impedance network which relates the voltages in accordance with the envelope of vibration so that the actual compensations at the individual guns are related to the actual current changes at the respective guns.

Abstract: An improved video amplifier arrangement with wideband D-C gain control is disclosed for use in a video display device of the type for displaying character information. The video amplifier includes an open-collector, TTL logic gate for receiving digital voice signal information which is then coupled to a cascode amplifier circuit for amplifying the video information and applying the same to a control element of an associated cathode ray tube. A D-C amplifier is provided having an adjustable element in its base input for applying a selectable D-C voltage thereto. The D-C amplifier includes an emitter resistor which is also connected to the open collector of the logic gate whereby the current developed by the D-C amplifier and applied to the emitter load resistor further determines the load current through the TTL logic gate. This, in turn, controls the level of pulse amplitude of the digital video information and serves as a video gain or level control.

Abstract: A digitally controlled CRT display system providing display intensity levels having equal ratios of luminances for consecutive steps over a plurality of brightness control settings. The digital video is added to a digital brightness code and the sum is converted to an analog signal that is coupled to the cathode of the CRT. The digital-to-analog converter provides a transfer characteristic such that the consecutive gray shade steps have a constant ratio of luminance.

Abstract: A system for controlling the emission of a device having a sense electrode for sensing a measure of an emission species from a source within the device. The sensed measure of the emission species is converted to a control signal. The output of the source is modified in response to the control signal by varying the time during which the source emits the emission species.

Abstract: Apparatus for controlling the intensity of a display on a cathode ray tube wherein the control signals are DC through several megahertz and a control loop maintains the average value of the control signal on the grid of a cathode ray tube relatively constant. Low frequency and high frequency signals are applied to the tube through separate circuits which are coupled together to provide coincident high pass and low pass -3 db crossover points so that all control signals applied to the tube are substantially equal over the entire bandwidth.

Abstract: An automatic intensity control circuit is provided for maintaining a constant perceived display brightness in an oscilloscope under varied operating conditions. The circuit includes an averaging circuit, a translation circuit, and a multiplier circuit to develop a cathode-ray tube grid bias control voltage which is inversely proportional to the duty cycle of the time-base sweep gate signal. Two or more such automatic intensity control circuits may be multiplexed for multi-trace oscilloscopes to maintain a constant perceived brightness when alternating between two or more traces.

Abstract: A radar system in which the time duration of video pulses corresponding to echo returns is increased as a direct function of the range of the return. On a PPI visual indicator, the visibility of long range targets is thus enhanced by increased size without distorting the display of short range targets and clutter.

Abstract: In apparatus including a cathode ray tube, electrical circuitry for preventing "burn" spots in the phosphor of the cathode ray tube. The protective apparatus includes means to measure the rate of change of deflection of the electron beam of the cathode ray tube and means to measure the brightness level of the electron beam. The absolute value of the rate of change of the deflection of the beam is divided by the brightness level of the beam to produce a signal which is compared to a reference value. If the dividend exceeds the reference value, the CRT is shut down as in the preferred embodiment by blanking the cathode ray tube beam.

Abstract: A video amplifier for decoding a digital signal input and providing at least three video brightness levels plus a black level to a cathode ray tube is disclosed. The amplifier includes input logic decoding circuitry for providing control signals to a plurality of switching elements which vary the voltage level of a video output signal. The video signal has at least four discrete voltage levels corresponding to a black, dim, normal, or bright display. The amplifier is preferably mounted on the socket of the cathode ray tube and provides a bandwidth on the order of 75 to 100 MHz.

Abstract: Each beam of a multi-electron beam display device is controlled to achieve uniformity of the displayed image. A collector senses the electron current of each beam. The level of the electron current of each beam is stored in a memory. When a particular beam is to be modulated, the memory is addressed so that the electron current level information for that beam is read out. The stored information and the incoming image element brightness information are combined to modulate the particular electron beam.

Abstract: A method and circuit for detecting spurious transitions ("glitches", herein) upon a digital signal utilizes a test for such a glitch condition dependent upon the digital signal level and upon the polarity of subsequent transitions within a discrete sampling period to allow for the detection of any type of glitch. A simultaneous display for the sampled digital data and for the detected glitch information further allows a convenience to an operator analyzing the data. Further, the glitch detector is used as a trigger for retrieving selected portions of the sampled digital signal.

Abstract: A charged particle apparatus wherein a charged particle beam irradiates an object to be observed and secondary emissions such as secondary electrons thus emitted from a surface layer of the object are detected. A signal indicative of the detected secondary emissions is applied to a control grid of a cathode ray tube to modulate an electron beam irradiating a fluorescent screen thereof. A detector detects the electron beam intensity of the cathode ray tube and minimum and maximum or peak values of the detected electron beam intensity are compared with predetermined reference signals to obtain deviation signals indicative of the difference therebetween. The signal applied to the control grid of the cathode ray tube is controlled in accordance with the deviation signals.

Abstract: A variable length vector display system allows visual indication of the sd and direction of aircraft or moving vehicles, maintaining a constant illumination on the face of a cathode ray tube independent of the vector length or vector movement. The vector length from the target vehicle coordinate points to the predicted intercept coordinate points are displayed. Voltages defining the origin and the end point of a vector to be displayed are coupled through respective comparator and arithmetic units, scaled to provide a deflection factor, multiplied, and coupled through respective controlled integrator circuits. The integrators are controlled by a variable gate which operates as a function of the input signal, thereby varying the on-off time of the integrators for simultaneous operation. Output signals from the integrator circuits are coupled to respective X and Y deflection circuits of a cathode ray tube load.

Abstract: Today's cathode ray tube oscilloscopes are widely used throughout the world and form an important basic tool in many industries. An apparatus to modulate the cathode ray display intensity, thereby enhancing the oscilloscope's capabilities in that it can now make more accurate measurements and, in effect, increase its band width, is disclosed. The apparatus to facilitate this effect is light weight, low cost, and easily connected to almost all oscilloscopes now in use.

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.

Abstract: Electron beams in a cathodoluminescent display device are modulated utilizing a means for generating a voltage proportional to the instantaneous electrical charge on the cathodoluminescent screen and means for generating a periodic reference waveform having a peak voltage proportional to a sampling of the incoming video signal. A differential amplifier compares the voltage proportional to the electrical charge on the screen to the instantaneous voltage of the reference waveform. A regulator controls the flow of electrons to the screen so as to force the voltage which is proportional to the instantaneous screen charge to approximate the reference waveform voltage.

Abstract: A system providing a substantially gapless continuous line display of an analog signal as a function of time on a television monitor. The input is digitized and each level of quantization corresponds to one of the raster display lines to give proper vertical deflection. During each line of raster scan an oscillator and counter sequence the input address to a memory through a desired number of horizontal sampling positions, requiring an address of the order of 8 bits. Each address gives an output of several bits giving in digital form the instantaneous y coordinate of the signal. This is digitally compared with the digitized associated raster line number in a first digital comparator. This is also stored in a register strobed from the above-mentioned counter just before each change of address. The raster line number and the stored previous output are digitally compared in a second digital comparator.

Abstract: Circuit to apply an offset voltage to be added to a charge storage signal depositing a charge on a radially swept charge storage surface so that the charge storage signal is a minimum at the center of the surface and a maximum at the outer edges of the sweep. This reduces or eliminates the charge integration in the area where the sweep lines converge.

Abstract: In a cathode ray tube display system, characters are generated for display either as matrices of dots or as sets of strokes on the lines of a parallel horizontal line raster.

Abstract: In accordance with illustrative embodiments of the present invention, data signals, particularly well logging data in analog or digital form, is recorded by a cathode ray tube recorder. A representation of the CRT beam is repetitively swept across a recording medium while being modulated with representations of the well logging signals. This modulation varies as a function of the rate of change of the well logging signals to produce an even density recording. Coding of the recording lines or traces and the areas between selected traces can be accomplished. This coding of the lines is also varied in dependence on the well logging signal rate of change to produce a uniform coding presentation. Depth information can be recorded on the recording medium by writing depth numbers and depth lines on the record medium. Moreover, a section by section visual presentation of the data can be produced while it is being recorded.

Abstract: A beam of charged particles has its alignment and brightness alternately controlled in accordance with the current of the beam. The measurements of the current and any corrections for alignment or brightness are made when the beam is not applied to a target.

Abstract: An intensity control system for a cathode ray tube (CRT) is disclosed. The system provides precise intensity control for a CRT whose control characteristics are only slowly varying. Precise intensity control is provided by measuring the cathode ray tube beam current. The beam current is set at a desired value without producing an image on the tube face. Thus, tube intensity can be set without fogging photoresponsive media which is in position for exposure by images on the cathode ray tube screen. The intensity may be set to a value determined by a manually adjustable intensity control. The intensity is preferably set by iterative threshold comparison of the actual beam current with the value corresponding to the setting of the intensity control. A unique threshold comparison circuit provides precise comparison between the reference level set by the intensity control and the actual beam current.

Abstract: A multiple automatic brightness control for a television receiver including a first automatic brightness limiter (ABL) circuit responsive only to relatively long duration changes in brightness-producing current and a second ABL circuit responsive to brightness-producing current changes of shorter duration than the first ABL circuit. Both ABL circuits have threshold levels below which they are not responsive to brightness-producing current changes, but the threshold level of the second ABL circuit is higher than that of the first so that, while the second ABL circuit responds more quickly than the first, it does so only for higher amplitude changes in the brightness-producing current.

Abstract: An amplifier for driving a color image reproducing device includes a first transistor the base of which is capacitively coupled to a source of color difference signals. The emitter of the first transistor is direct current coupled to the base of a second transistor. The collector of the second transistor is direct current coupled to the base of the first transistor. The emitter of the second transistor is coupled to a source of a predetermined voltage. The emitter of the first transistor is direct current coupled to the emitter of a third transistor of opposite conductivity type which serves as a luminance signal amplifier. The first and third transistors form a matrix amplifier operative to generate a color signal at the collector of the first transistor.

Abstract: An automatic control for the optimum control voltage during the line flyback time between the control electrode and the cathode of an ACT gun in a television pick-up tube. A variation in the cathode potential during the line flyback requires inter alia an adaptation of the control electrode potential. Without this adaptation a too small beam current on the target would result in an insufficient erasing action while a too large beam current would result in an inadmissible dark current with the risk of persistence upon display (afterglow). In the circuit arrangement a measurement of the beam current is effected through a specific choice of the lens pulse duration at the gun, which beam current becomes available for the erasing action on the target during the line flyback time, and through comparison with a reference value a variable pulse generator is controlled for supplying the control electrode pulse with a given pulse height during the line flyback time.

Abstract: A square-shaped electron beam is stepped from one predetermined position to another in a line-by-line scan to form a desired pattern on each chip of a semiconductor wafer to which the beam is applied. At each of the predetermined positions, the beam is on, off, or on for a portion of the time period at which the beam is disposed at the predetermined position. The beam also can be offset both along its direction of movement and perpendicular thereto at each of the predetermined positions. Control of this movement of the beam is obtained through utilizing a memory with no change being made in the memory if the predetermined position at the next line does not have any change from the predetermined position at the line along which the beam is moving.

Abstract: A video amplifier for driving an electron beam intensity controlling electrode of a cathode ray tube comprises at least one solid state high speed binary switch which is connected via a coupling capacitor to the controlling electrode while a D.C. restoration means eliminates the chance of any droop in D.C. level of the signal fed to the controlling electrode.

Abstract: An electron gun for use in a cathode-ray tube is provided with two control grids between the cathode and an accelerating electrode. The control grids are both provided with separate control voltages bearing the same intensity-modulation information for control of the electron beam from the cathode. The two control voltages are caused to vary, one according to a linear function of the variation of the other. When this linear function is caused to have a particular slope, the area of the cathode which emits the electron beam remains approximately constant over a wide range of control voltage.