Abstract: Phase reversal of solely the chrominance component of only alternate frames of an NTSC format signal prior to pre-emphasis and again subsequent to de-emphasis permits simpler and less costly filter structure to be employed without any loss of filtering capability.

Abstract: Aliasing in detected image samples is substantially reduced by a spatial low-pass prefilter employing a diffusing surface variably spaced from an imager and situated in the path of projected image light to cause greater blurring in lower resolution regions of the imager than in higher resolution regions thereof, such that the cutoff spatial frequency varies continually in accordance with the variable resolution of the system.

Abstract: The use of a Galilean telescope, situated in between the two lasing mediums that are located within the resonant cavity of a single longitudinal mode hybrid laser, increases the effective mode volume and, hence, the amount of lasing energy that can be derived from such a hybrid laser.

Abstract: An image of periodic color-filter stripes derived by a periodic lenticular array is made to coincide with a periodic pattern of discrete solid-state light cells of an imager, despite manufacturing tolerance errors in the values of the respective periods of the filter and array with respect to the value of the period of the imager. This is accomplished by angularly displacing each of the respective axes of the periods of the filter and imager, with respect to the axis of the period of the array, by a calculable amount.

Abstract: A green-manifesting blank comprised of yellow and cyan dielectric stacks, one on top of the other, supported by a transparent substrate can be used to fabricate a green, yellow or cyan, and white color-encoding filter having any arbitrary given spatial pattern by combining dry-etching and wet etching, if the top layer of the bottom stack is composed of a material which is inert to a given wet etchant and the bottom layer of the top stack is composed of a material which is etched by the given wet etchant. Alternatively, the wet etching can be dispensed with if, after completion of the color-encoding filter, the filter is covered with an overcoat material exhibiting an index-of-refraction substantially equal to that of the bottom layer of the top stack.

Abstract: Each of a plurality of circuit paths between a common input terminal and respective output terminals includes a switching device which can be switched between a high and a low impedance state. When a device in one path is switched into its low impedance state in response to a path selection signal, the devices in the remaining paths automatically are switched to their high impedance state in response to a portion of the signal to be passed through the path with the low impedance device. In this way, one of the circuit paths may be selected for coupling the input terminal to a selected output terminal and all other circuit paths are automatically blocked.

Abstract: A given type of authenticating device operates as a diffractive subtractive color filter that exhibits a reflectivity spectrum that includes a peak occurring at a wavelength that varies as a substantially linear function of the angle of incidence of polychromatic illuminating light having a particular polarization. The verification technique involves simultaneously illuminating a sample device over a range of angles of incidence by the polychromatic light, and then employing the reflected light from the sample to illuminate a reference device known to be genuine over the same range of angles of incidence. A sample device is indicated as being genuine only if both the respective intensity ratios of the light reflected from the reference device to the polychromatic light and to the light reflected from the sample device exceed respective threshold values.

Abstract: Noise reduction is achieved, without the introduction of noticeable artifacts in the displayed image, using (1) a non-ringing, non-aliasing, localized transfer, octave-band spectrum analyzer for separating the video signal representing the image into subspectra signals, (2) separate coring means for one or more of the analyzed subspectra signals, and (3) then a synthesizer employing one or more non-ringing, non-aliasing filters for deriving an output image-representing signal from all of the subspectra signals.

Abstract: The respective pixel stages of an electro-optical transversal filter may be intimately associated with corresponding stages of a CCD shift register means in a monolithic structure on an integrated chip. The shift register means, which operates to forward a pre-selected one of a set of analog reference weights to each of the transversal filter pixel stages, permits the transversal filter to be used in an electro-optical correlation means having a very high effective computation rate.

Abstract: The use of a rhomboid-shaped phase grating to derive, from polychromatic input light, plus-one, minus-one and zero diffraction order output beams each of a different independent color.

Abstract: An optical beam switch is provided in a multiple beam optical disc record and playback system. Current systems for very high data rate optical disc mass memory apparatus include requirements for near-continuous recording of data using two separate turntables in a single apparatus. To reduce cost and complexities in the system as well as power requirements, the optical system includes a beam switch that allows a single record laser and modulator to be shared between two turntables. In accordance with the system a half-wave plate is shifted into and out of the beam path to effect polarization change of the light beam. A polarizing beam splitter, which follows the half-wave plate in the beam path, shifts the light beam in one of two directions depending upon the polarization of the light beam or, in other words, the position of the half-wave plate.

Abstract: The use of a return-to-zero (RZ) sample and hold circuit between the CCD delay line circuit and the low-pass filter of the analog signal translation system provides a steeper high-frequency roll-off of the output from the low-pass filter than does a non-return-to-zero (NRZ) sample and hold circuit, and, therefore, produces less attenuation of high-frequency components of analog signal, such as the color-carrier of an NTSC color television signal.

Abstract: The setting of a screw-operated tapered rod is used to control the separation between a spring-loaded beam element and a base element of a microtranslator with a positioning resolution of the order of 200 nanometers or less in a direction substantially parallel to a given single axis. A microtranslator assembly incorporating two such microtranslators oriented substantially perpendicular to one another is suitable for aligning a laser diode with a single-mode optical fiber to effect maximum coupling of light therebetween.

Abstract: Three embodiments of an improved smear reduction technique, for reducing substantially all the smear in a CCD field-transfer imager system due to the presence of a bright spot in the projected image, regardless of whether the bright spot remains fixed or whether the bright spot moves between successive field periods. Prior smear reduction techniques were not effective with respect to a moving bright spot. Structurally the improved system employs a CCD field-transfer imager including a line register, in addition to conventional A and B, for collecting smear charge produced in the A register during each successive field period. The smear line register cooperates with associated circuitry to provide the improved smear reduction. In a first and second of the three embodiments, the imager includes a conventional C line register for deriving a smeared video output applied as an input to the associated circuitry, and the smear line register is an additional line register, known as the D register.

Abstract: A pair of oppositely poled PIN diodes is connected in series across a reactive element. First and second switching circuits responsive to a common control network are serially connected between high and low voltage points. The junction between the switching circuits is connected to the common junction of the PIN diodes. When the first switching circuit is made non-conductive and the second conductive, the PIN diodes are forward biased. When the first switching circuit is made conductive and the second non-conductive, the PIN diodes are reverse biased. In this way the reactive element is switched into and out of a tuned circuit.

Abstract: A variable index-of-refraction optical medium of certain minimum thickness and periodicity with respect to the wavelength of incident light--if it meets certain specified constraints with respect to (1) relative indices-of-refraction of both its internal structure and that of its surroundings and (2) relative values of incident wavelength to periodicity and the relative indices-of-refraction--operates to produce both angularly-dependent subtractive-color filter reflection spectra and subtractive-color filter transmission spectra in accordance with its physical parameters. Such filters are suitable for use as authenticating devices for sheet-material authenticated items.

Abstract: An impedance matching network suitable for tuning an antenna includes a plurality of reactive elements and control circuits for selectively switching these elements into and out of the circuit. Each control circuit includes a pair of oppositely poled, normally reverse biased, PIN diodes connected in series across a reactive element and apparatus including a selectively controllable radiation responsive element for forward biasing the PIN diodes to thereby effectively switch a reactive element out of the network. In one arrangement, the reactive elements are formed from spaced, helically wound sections of a hollow conductive tube with the biasing voltages for the PIN diodes carried by conductors located within the tube.

Abstract: Dark current compensation is obtained in a charge transfer circuit such as a charge coupled device (CCD) delay line by subtracting from each charge packet, after each predetermined number of shifts of that charge packet, a certain amount of charge. In a preferred form of the circuit, a reference charge packet is periodically introduced into the delay line and the amount of dark current it has accumulated after a given number of shifts is sensed and is employed to determine how much of each charge packet will be periodically removed.

Abstract: Significant features of interest of each pulse shape, amplitude and time of occurrence characteristics, are preserved in a detection circuit that (1) employs a tapped delay line as part of means for deriving a pedestal signal at the predicted current level of an input signal to the delay line, the level of the pedestal signal being determined by extrapolating the slope and level of a running segment of the past history of the input signal level to the delay line, (2) subtracts the derived pedestal signal level from the actual level of an applied input signal, comprised of pulses superimposed on an unknown and variable background signal, to produce a difference level, (3) indicates the occurrence of a pulse by this difference level being at least equal to a threshold level, (4) selectively applies the applied input signal as the input signal to the delay line when the difference level is below the threshold level, and (5) selectively applies the pedestal signal as an input signal to the delay line when the dif

Abstract: The circuits include a floating diffusion, a source supplying a controllable amount of charge to the floating diffusion and a charge coupled device (CCD) reference register for periodically removing a fixed amount of charge from the floating diffusion. A feedback circuit senses the average voltage at the floating diffusion and adjusts the controllable amount of charge supplied to the diffusion to maintain its average voltage-level constant. The feedback circuit may be employed automatically to control the direct voltage bias at the input electrode of a DDC signal register. It may alternatively be employed to control a radiation source serving as the input to the system, or to operate a circuit for indicating the frequency at which the reference CCD register is being driven, or as an input to a current mirror amplifier.