Abstract: An imaging device such as a silicon vidicon has a wafer of single crystal semiconductor material having an input sensing region and a charge storage region. A potential barrier is included within the input sensing region for controlling blooming. A passivation region is also included within the input sensing region to stabilize the atomic energy level along a first surface of the wafer. An anti-reflection layer of zinc sulfide and an anti-reflection layer of magnesium fluoride or Cryolite are sequentially deposited on the first surface of the wafer. The two anti-reflection layers form an anti-reflection region which enhances the quantum efficiency of the device in the wavelength range of 400 to 500 nanometers. Each of the layers has an optical thickness substantially equal to a quarter of the wavelength of light incident on the device. A method of forming the anti-reflection region is also disclosed.

Abstract: In a tuning control system for a television receiver, an analog AFT signal is sampled during blanking intervals when the amplitude of the video carrier is relative constant and therefore cannot affect the amplitude of the AFT signal significantly. This reduces the AFT filtering requirements.

Abstract: Charge transfer devices typically include a periodically reset floating element output stage coupled to an FET amplifier for sensing the transferred charges. For reducing both low-frequency l/f noise and high-frequency reset noise, the duty factor of the device clocking signals and the reset signal are picked so that at a selected multiple of the clock signal repetition rate, the information component is in phase quadrature with the reset noise component. The charge transfer device output signal is then synchronously detected with a reference signal which is in phase with the selected multiple of the information component.

Abstract: A digital phase-lock-loop circuit includes a generator that produces a horizontal rate output signal at a controlled frequency and a phase detector responsive to the output signal and to an incoming synchronizing signal. The phase detector is coupled to the generator control port via a loop filter. When the phase between the output signal and the synchronizing signal that synchronizes the phase-lock-loop circuit changes as a result of, for example, head switching in a two-head VTR that supplies the synchronizing signal, a signal representative of such phase change is produced. The phase change representative signal is fed forward to the generator, by bypassing the loop filter of the phase-lock-loop circuit. The phase change representative signal produces an immediate phase shift of the output signal such that the loop filter is not affected by the head switching.

Abstract: A video display apparatus incorporates a picture tube, such as a square-planar picture tube, that includes a phosphor screen located on a faceplate having an aspherically curved geometry that produces a relatively flat surface contour. Deflection circuitry generates line and field scanning currents in respective line and field deflection windings to enable the electron beams of the picture tube to scan a raster on the phosphor screen. The electron beams are subject to a scanning error that results in raster distortion, such as side pincushion distortion. A parabola generator produces a parabolic modulation of the scanning of the electron beams to generally correct the raster distortion while retaining a residual error due to the aspherically curved geometry of the faceplate.

Abstract: Parallelled charge transfer channels have multiple-phase-clocked gate electrodes overspanning them in one of a number of arrangements conditioning the transfer of charge packets in opposing directions in adjacent charge transfer channels. Three-phase, four-phase, five-phase and six-phase clocking arrangements constructed in three layers of polysilicon embody the invention.

Abstract: A dynamic focus voltage generating circuit for television generates a parabolic voltage at the horizontal rate that is responsive to a synchronizing signal. The parabolic voltage is generated from a sawtooth waveform having an upramping portion, a downramping portion and a flat portion such that only the length of the flat portion of the sawtooth waveform varies when the frequency of the synchronizing signal changes.

Abstract: Line and field deflection circuits generate line and field deflection currents in respective line and field deflection windings to scan a raster on the phosphor screen of a square-planar picture tube having an aspherical faceplate. The asphericity of the faceplate subjects the scanned raster to gullwing distortion. A gullwing distortion correction circuit is responsive to signals repeating at line and field rates, respectively, for modulating the field deflection current during a line deflection period within the field deflection trace interval in a manner that corrects gullwing distortion of a corresponding raster scan line.

Abstract: An intensified charge-coupled image sensor comprises an image intensifier section and a header assembly. The header assembly includes a charge coupled device and an insulative header for retaining the charge-coupled device. An imaging aperture having a sidewall is formed in the insulative header. The imaging aperture is disposed about an optical axis of the image sensor. A conductive layer for preventing electrostatic charge buildup resulting from the impingement of photoelectrons emitted from a photoemissive cathode is provided on a first major surface of the header and on the sidewall bordering the imaging aperture. The header includes an electrode surface having a plurality of discrete contact pads thereon. A header input member has a substantially rectangular portion attached to a first major surface of the insulative header and an annular portion attached to the image intensifier section of the image sensor.

Abstract: An image display including a viewing screen comprising spaced elemental image areas and a light-absorbing matrix of partially-graphitized carbon black adjacent these areas. The matrix may be made by overcoating a stencil and stencil support with an aqueous slurry of the carbon black, drying the overcoating, and then removing the stencil and overlying overcoating.

Abstract: A so-called "solar-blind" photomultiplier tube includes an envelope having a sidewall and an input faceplate formed from an ultraviolet transmitting filter. A photoemissive cathode is disposed within the envelope for providing photoelectrons in response to radiation incident thereon. The cathode has an intrinsic responsivity extending from the near-ultraviolet portion through the visible portion of the electromagnetic spectrum; however, the filter faceplate transmits only the ultraviolet portion of the spectrum to the photoemissive cathode. The combination of the filter faceplate and the photoemissive cathode therefore limits the tube to a responsivity within the wavelength range of about 300 to less than 400 nanometers.

Abstract: An input signal for controlling a television power supply has "power-on" and "power-off" signal states. When the input signal is in the "power-on" state, it couples a clock signal to a primary winding of a transformer causing an alternating current voltage that is conductively isolated from the input signal to be developed across a secondary winding of the transformer. When the input signal is in the "power-off" state, it decouples the clock signal from the primary winding so that no alternating current voltage is developed across the secondary winding. The signal across the secondary winding is demodulated in a demodulator that produces a control signal that is conductively isolated from the input signal. The control signal is coupled to a regulator of the power supply. A power-on state of the control signal occurs when the alternating current voltage is developed at the secondary winding terminal. A power-off state of the control signal occurs when the alternating current voltage is absent.

Abstract: Improved signal modulating circuits for a light valve projector are disclosed which are capable of increasing the magenta efficiency of the projector. The projector has an input bar plate having slots, a deformable light modulating medium and an output bar plate having slots. The control circuits generate a first control signal for red and a second control signal for blue. The light modulating medium is modulated in accordance with the red and blue control signals. The control circuits enhance the magenta modulation of the light modulating medium by generating a third control signal for magenta.A first circuit provides a magenta control signal whenever there is a magenta component which is the result of simultaneous inputs from the red and blue signals. A separate signal level for magenta is derived from the red and blue signals and a separate magenta carrier frequency is used which will cause magenta light to pass through slots in the output bar plate.

Abstract: First and second output signals are taken from a floating element in a CCD charge transfer channel and from the terminal drain diffusion of that CCD charge transfer channel. The floating element is part of an electrometer, and the electrometer response is wide-band sampled at the CCD charge transfer channel clocking rate. Current flow through the terminal drain diffusion is sensed by the input circuit of a low l/f noise transresistance amplifier. Continuous-frequency-spectrum low-noise output signal is generated from the low-frequency components of the transresistance amplifier response and from the high-frequency components of the processed second output signal. Subsequent filtering removes unwanted clock and aliased frequency components.

Abstract: In a deflection circuit that operates in any scan frequency selected from a plurality of frequencies, the supply voltage that is DC-coupled to a first terminal of a trace capacitor is increased when the scan frequency increases. The deflection circuit includes a diode modulator that is controlled by a modulation voltage having an AC component voltage that varies at a vertical rate. The increase in the supply voltage causes an increase in a DC component voltage of the modulation voltage that is coupled to a second terminal of the trace capacitor such that the voltage in the trace capacitor increases in the same proportion as the supply voltage. The proportional increase in the trace capacitor voltage maintains the raster width unchanged when the scan frequency increases.

Abstract: A television centering circuit includes a non-linear conduction network coupled in series with an inductance. The series arrangement is conductively coupled in parallel with a horizontal deflection winding. A control circuit for the non-linear conduction network utilizes negative feedback to sense and control the current in the inductance when the current is of a first polarity, thereby regulating the average value of the current in the inductance and in the deflection winding to provide raster centering.

Abstract: A vertical rate parabolic voltage at a peak-to-peak amplitude that is adjustable is generated in an integrator from a sawtooth input voltage. The parabolic voltage at an output terminal of the integrator is applied to a source of a B+ operating voltage to form a parabolic component voltage of the B+ operating voltage that controls the amplitude of a trace current in a horizontal deflection circuit output stage. The parabolic voltage is adjusted in peak-to-peak amplitude to provide east-west pincushion correction of the raster. The minimum level of the parabolic voltage in each vertical period is automatically maintained at an unchanged level that is approximately zero volts throughout the range of east-west adjustment. Because the minimum level of the parabolic voltage remains unchanged, the maximum level of the B+ operating voltage, a level that occurs in the center of each vertical interval, also remains unchanged throughout the range of east-west adjustment.

Abstract: A periodic signal, at the frequency of the AC mains supply voltage, contains signal pulses, each having a duration that is substantially shorter than half the period of the AC mains supply voltage. The periodic signal is coupled to a high frequency transformer to form a periodic output signal that is applied to a time-of-day measurement circuit that provides time-of-day display information for a television receiver. The transformer provides conductive isolation between the time-of-day measurement circuit and the AC mains supply voltage source.

Abstract: An imaging device such as a silicon intensifier tube (SIT) has an envelope closed at one end by an input faceplate and at the other end by a camera section which includes a silicon target. A novel appendage processing assembly is in communication with the envelope for forming a photoemissive cathode on an interior surface of the input faceplate. The novel appendage processing assembly includes a conductive tubular sidearm which is attached to the envelope. A chamber is attached at one end of the sidearm. The chamber is closed at the other end by a stem portion having a plurality of conductive stem leads extending therethrough. A contact spring and a connecting rod are provided within the chamber to electrically connect the sidearm to one of the stem leads. At least one alkali metal vapor source and preferably three alkali vapor sources are disposed within the chamber and connected between two of the stem leads to permit electrical resistance heating of the vapor sources.

Abstract: A high definition television signal for use in a studio production facility is formed by scanning an image in progressive rather than interlaced fashion to form luminance and first and second color-difference signals and by reducing the resolution of the color-difference signals in both the horizontal and vertical directions but leaving the resolution of the luminance signal substantially unaltered.