Abstract: A pulse width modulated control signal for use in motor control and with power supplies is generated by a dual-mode controller having variable frequency control in a discontinuous current operating mode. The controller also provides control in a continuous current operating mode, and makes a smooth transition therebetween.

Abstract: An active or translating device having distortion is associated with a controllable predistortion circuit or linearizer. A filter sampler arrangement samples the desired fundamental-frequency signal and its second harmonic. A control circuit forms the ratio of the amplitude of the second harmonic divided by the amplitude of the fundamental-frequency signal, and controls the linearizer to minimize the ratio.

Abstract: A method for welding together the broad faces of two conductive sheets increases the reliability and consistency from weld to weld. The sheets are accessible from only one side for parallel electrical resistance welding. The electrical resistance between one sheet and the other is measured and taken as an indication of the amount of dirt or corrosion in the interface between the sheets. The measured resistance is compared with a predetermined standard. If the resistance exceeds the standard, the faces are cleaned. If the resistance is below the standard, electrical power is applied to fuse the sheets together.

Abstract: A heat exchanger includes a porous cylindrical sleeve with a bore into which liquid coolant is admitted. The liquid permeates the sleeve but cannot leave the outer surface. A pipe surrounds the sleeve. The pipe has a cylindrical outer surface and an inner surface defining protrusions and vapor channels about the protrusions. The inner ends of the protrusions bear against the outer surface of the sleeve. A plurality of helical channels are helically arranged about and in thermal contact with the outer surface of the pipe. The ends of the helical channels are coupled to plenums. Each plenum is coupled by a pipe and a fluid disconnect to one end of a thermal loop including a heat source. Heat-laden vapor passes through the helical channels and is cooled to liquid. The heat is withdrawn into the pipe and passes through the protuberances to vaporize the liquid near the surface of the porous sleeve. The resulting vapor is collected and coupled to a condenser.

Abstract: A mast defined by three flexible longerons with cross elements coils into a canister. Extension and retraction are controlled by three axially oriented lead screws which engage protuberances spaced along the longerons. The lead screws are mutually synchronzied by an annular planet gear, and are driven by a spiroidal gear set. At a predetermined mast extension, motor drive is switched over for rotation of the mast rather than extension-retraction. The switch over is controlled by an actuator in the form of a movable guide element dimensioned to clear normal-sized protuberances but to be seized and carried by an oversize protuberance at the desired mast extension. The actuator is coupled to a lock which unlocks the annular gear to the canister so that motor drive results in mast rotation. An auxiliary lock allows re-locking of the canister to the support structure for allowing resumption of the mast extension-retraction mode.

Abstract: A multichannel processor for signals modulated onto a common IF frequency includes first and second analog-to-digital converters (ADC) for first and second channels, respectively. Each ADC receives a 4XIF frequency clock for producing digital samples, which are applied to a pair of gates for alternately coupling the digital signal to two signal paths. Each signal path alternately negates and does not negate the signals passing therethrough, thereby generating baseband I and Q signals for that channel. Since each channel has a separate ADC, there may be amplitude and temporal error between the channels. One of the channels is selected as a reference, and uses a pair of interpolators to produce samples representing the I and Q signal values at a common time between clock pulses. The other channels include controllable interpolators which are adjusted so that their I, Q common times correspond to that of the reference channel.

Abstract: A dedicated set of four input pads or pins of an LSI chip provides access by a serial data line to macrocells or other partioned logic of the LSI for individual test. A macrocell is connected to the remainder of the logic by a pair of multiplexer/test register combinations, one at the input, and one at the output of the macrocell. In a normal operation mode, the multiplexers connect each macrocell to the next, for normal signal flow. Under control of test signals, the test registers may be selectively loaded with data from the serial data bus, and the multiplexers may be switched to apply test data from the test register to a macrocell. The output multiplexer of the macrocell routes the resulting processed test data to the output test register, so it may be read out in serial form while normal operation resumes.

Abstract: An optical recorder such as a data recorder has an interchangeable, prealigned laser diode/lens module arrangement which can be readily replaced without complex realignment of the recorder. The module includes a cylindrical outer housing/heat-sink, and a tiltable yoke within the outer housing/heat-sink. A heat pump such as a thermoelectric element has a hot side coupled to the yoke, and also has a cold side. A combination mount is at least thermally cantilevered from the cold side of the thermoelectric element, and is thermally isolated from adjacent structures. A laser diode is bonded to a structure within the combination housing, and a lens is loosely mounted at the light-emitting end of the combination housing. The module is prealigned by operating for a period sufficient to achieve thermal stability in a fixture which is dimensionally identical to the optical recorder with which the module is to be used.

Abstract: A method for welding two pieces includes juxtaposing the pieces and monitoring the temperature of the region to be welded. Energy is applied at a time rate sufficient to raise the temperature of the region to be welded at a rate exceeding a predetermined value. Once a predetermined temperature is reached, that temperature is held for a predetermined time. The rate of rise of temperature is 70% of the final or predetermined temperature in 20% of the predetermined time. After the weld is made, the rate of fall of the temperature exceeds a predetermined value. Quenching may be used to achieve the desired rate of fall.

Abstract: A switching power supply includes push-pull power switches driven by first and second conjunction gates. The conjunction gates are coupled to receive the output of a flip-flop, together with the antiphase outputs of a binary divider which divides down the output of the flip-flop. The flip-flop is driven recurrently by sync to enable one of the conjunction gates, and the binary divider steers the enablement alternately. When the output voltage or current crosses the design threshold, a comparator is triggered to produce a shut-down signal which is applied to the reset input terminal of the flip-flop to reset it. Delay in the flip-flop is avoided by also applying the shut-down signal to the conjunction gates. The maximum possible duty cycle is extended by initiating switch conduction at a predetermined short time after initiation of the sync pulse.

Abstract: An infrared imager includes an array of imager elements. Infrared radiation is focussed onto the array by a lens assembly including a plurality of lens elements. The imager array and the lens are within a cold box which includes an infrared-transparent window. For low noise, a spectrum-limiting filter is also located within the cold box, between the lens assembly and the window, at or within the pupil relief distance of the lens assembly. The pupil relief distance is extended by the use of at least one aspheric surface for one of the lens elements of the lens assembly. The mounting structure of the filter is the aperture stop for the infrared imager. The field of view may be reduced, if desired, without significant effect on the noise performance by use of a telescope including a second lens assembly optically identical to the first lens assembly, operated in conjunction with a confocal large-diameter lens assembly.

Abstract: A light-activated PIN diode switch arrangement is coupled to a source of direct voltage and to a load for control of the flow of load current. The PIN diode switch arrangement is connected so as to be electrically reverse-biased, so that no current flows therethrough. A source of light is coupled to the active portion of the PIN diode switch arrangement for rendering it conductive when flooded with light. Higher reverse voltage capability, higher operating speed and lower overall forward resistance are simultaneously achieved by a plurality of series-connected PIN diodes by comparison with a single large PIN diode.

Abstract: A chip layout system lays out chips including adjustable-shaped domains of standard cells and fixed-size macrocells. The system orders those standard cells which have interconnections into binary pairs or groupings of two. The binary pairs are grouped in higher and higher order groupings based upon evaluations of the area of the grouping and the sum of the lengths of the interconnections. All possible permutations of placement configuration including some rotations of various elements are further evaluated and the final placement is established on the basis of a minimum area, minimum interconnect length criterion. During the processing, the aspect ratios of the various domains and grouping of domains are adjusted to optimize their placement on the chip surface.

Abstract: An automated LSI chip layout arrangement includes automated layout of the power bus distribution network. A complete interlocking mesh of buses is run in routing channels lying between groups of circuits to be powered. Each segment of the mesh powering net which affects the chip size is tested to see if it can be removed without adversely affecting the power distribution. If it can be removed, the segment is deleted. The next segment which is critical to the size of the chip is then tested, and the process is continued. Those segments of the power bus distribution network which do not affect the size of the chip are not eliminated. Thus, a low-resistance power distribution bus network is guaranteed, and chip size is minimized.

Abstract: In a dc-to-dc converter, alternating current or pulsating direct current produced by a cyclically switched power supply passes through semiconductor rectifiers or diodes. The rectifiers may be subject to unwanted conduction characteristics attributable to charge storage, which may result in cyclical current spikes during normal operation. A current sensor is coupled to sense a current which includes the cyclical spikes. A controllable attenuator or gain element couples the sensed current in a feedback loop to shut down the converter in the event of an overcurrent. To reduce the possibility of shut-down due to the normal cyclical current spikes, the attenuator or gain element is cyclically switched so as to reduce the sensitivity to the current spikes when they occur.

Abstract: A liquid toner applicator for elongated photoconductive film medium on which a latent electrostatic image has been formed includes an upper bearing surface for supporting moving film medium, which is spaced from a conductive block having an upper surface. The conductive block has slots cut into a toning region of its upper surface. During operation, pressurized toner wells through the slots into the region between the lower surface of the film and the upper surface of the block. The toner tones the latent image. The upwelling toner spills into fluid channels, which carry the toner which is not used to a catch basin. From the catch basin, a toner pump recirculates the toner. Downstream form the toning region, a further slot cut into the block communicates with a vacuum source to squeegee away excess toner which is not associated with the toned image. An air knife downstream from the vacuum squeegee includes a slot cut an an angle through the block and a pressurized air source therefor.

Abstract: A reduced size waveguide directional coupler assembly includes a first rectangular waveguide which is adapted to receive signal at an input port. A conductive septum parallel with a broad wall of the rectangular waveguide divides the signal into two portions flowing in first and second channels within the first waveguide. The septum may be centered between the broad walls, in which case the two signal portions and channel dimensions are the same, or the septum may be off-center, resulting in dissimilar amplitudes of the two signal portions. The coupler also includes a second waveguide. Branch waveguides or other coupling apertures open from the first channel into the second waveguide. That energy not flowing to the second waveguide from the first channel may be routed to an independent output port, or may be recombined with the energy flowing in the second channel and routed to a combined output port.

Abstract: A P-channel field-effect transistor includes an inherent junction diode. As it is normally used, the inherent diode is back-biased and therefore effectively out of circuit. An uninterruptible power supply arrangement including primary and backup voltage sources supplies uninterrupted power to a load by way of two or more P-channel field-effect transistors connected so that their inherent diodes conduct to provide an OR function, independent of field-effect operation of the field-effect transistors. A control circuit controls the gate voltage relative to the source voltage of each transistor to selectively short-circuit the inherent diode of that one transistor which is connected to the power supply which is to energize the load. This reverse-biases the other inherent diodes and effectively removes the other power supply from the circuit, so that power for the load is drawn only from the selected power supply, there is no diode forward junction potential reducing the load voltage, and no excess dissipation.

Abstract: A switch arrangement for interrupting signal flow on a microstrip transmission line includes an electromagnetically actuated conductive plunger extending through a hole in the dielectric plate on which the microstrip is formed. The strip conductor end adjacent the hole, and a spring conductive bridging element extends across the hole, fixed to one strip conductor and free to make contact with the other. The plunger is supported by a conductive diaphragm spring connected to the ground plane of the microstrip, thereby eliminating sliding contacts. When actuated, the plunger simultaneously lifts the bridging element free from the one strip conductor and short-circuits the other.

Abstract: A non-linear torque produced by an offset mass rotating on a shaft is balanced over 360.degree. of revolution by a lever arm mounted to the shaft extending in a direction opposite that of the offset mass and a spring means for generating a constant force in the direction of gravity at the opposite end of the lever arm.