Abstract: Display of alphanumeric characters symbols, graphs and other information in a dot-matrix form on a CRT is enhanced by modulating the CRT beam sinusoidally at twice the dot matrix clock rate to produce two full cycles of sinusoidal modulation for each dot space. The amplitude of the modulation is selected to be one-fourth the raster scan spacing of the CRT, whereby two sinusoidal cycles of modulation in each dot space more fully fills the space allocated to a dot display in the vertical direction as the electrons beam scans the dot space in the horizontal direction.

Abstract: An LC tank circuit in the collector of a power transistor controls the vertical modulation of the horizontal deflection of a CRT through additional deflection coils properly oriented. The tank circuit is tuned at a frequency nf for the desired modulation, where n is the number of cycles of oscillation of the tank for each drive pulse at a frequency (pulses per second) f, and each drive pulse is adjusted in width to one fourth or less of a cycle of the modulation frequency nf using an adjustable RC differentiating circuit and a threshold device to couple a squarewave signal at frequency f to the base of the power transistor.

Abstract: A three-pole double-throw switch is provided to selectively interrupt the video signal from an input connector to an output connector for display of white characters generated by a microprocessor on a dark screen of a CRT monitor, or vice versa, and route the video signal through an inverter for display of dark characters on white screen. One pole of the switch is used to provide the vertical sync signal to the power input terminal of the inverter, thus powering the select switch box solely from the transmitted vertical sync signal. A capacitor filters the power supply thus provided. The select switch box requires no external power and is virtually free of RF energy radiation while providing noise free data display with equal bandwidth response in both modes.

Abstract: Resolution of a dot-matrix character display system for a CRT is enhanced by storing two bits for each dot space, thus storing qMxn bits, where M is the number of dot spaces in a row, and N is the number of rows. The clock for reading M bits of a character in a row is increased by a factor q to generate q dots per dot space, while the CRT beam is sinusoidally modulated at the clock rate. The phase and amplitude of the modulation is selected to place the q dots displayed in a dot space at maxima of the modulation within a dot space of an MxN matrix, with a vertical displacement of .+-.1/4 raster scan width of the CRT.

Abstract: Display of alphanumeric characters and other symbols generated in a dot-matrix form on a CRT is enhanced by modulating the CRT beam sinusoidally at the dot matrix clock rate to produce one full cycle of modulation for each dot space with a phase to display a dot on a slope between modulation maxima of opposite polarity. The phase and amplitude of the modulation is selected to place the q dots displayed in a dot space between the modulation maximum of one polarity and a maximum of opposite polarity for each dot space of an M.times.N matrix, with a depth of modulation of .+-.1/4 raster scan spacing of the CRT.

Abstract: An improved color television transmission compatible with NTSC standards produces a controlled horizontal scan rate at about 15,768 Hz with 227 cycles of color subcarrier per line, and a controlled horizontal scan rate at about 60.070 Hz to produce frames of two interlaced fields each at a rate of about 30.035 Hz with 227.5 cycles of the color subcarrier per field phase shifted 180.degree. of the color subcarrier at the beginning of each field, thereby eliminating "chroma crawl," and reducing the size of the teeth in the "zipper" effect produced by NTSC encoded color at the edge of vertical color borders. The vertical scan rate is controlled by dividing a clock frequency of four times the color subcarrier by four to produce the color subcarrier, and dividing the clock frequency by some set of multiples to produce the horizontal scan rates with 227 cycles of color subcarrier per line plus one-half cycle.

Abstract: In a system for high resolution television achieved by vertical modulation of the horizontal scan at a frequency twice the color subcarrier, the modulation signal is derived from the color subcarrier at both the camera and receiver by squaring the color subcarrier sinusoidal signal, inverting the squared waveform, differentiating the inverted and uninverted square waveforms and from the combined differentiated pulses producing a train of pulses at a frequency twice the color subcarrier. This train is then applied to a transistor connected as a class B amplifier with the vertical deflection coil and a parallel capacitor as an LC resonant load. The current to the coil is provided by a regulated power supply that is adjustable to adjust the amplitude of the vertical deflection of the horizontal scan.