Abstract: A power combiner includes an input power splitter driving a plurality (N) of amplifiers. The amplifier outputs have Z.sub.0 output impedance and are coupled by transmission (TX) lines of Z.sub.0 characteristic impedance to the junction point of a lossless power combiner. Short-circuiting switches located .lambda./4 from the junction power disconnect failed amplifiers from the combiner. According to the invention, a number M<N of the shorting switches are open during normal operation, so the impedance presented by the parallel TX lines at the junction of the combiner is Z.sub.0 /M. An impedance transformer associated with the combiner transforms the junction point impedance Z.sub.0 /M to Z.sub.0 at the combined output port, for example, by a .lambda./4 line having an impedance .sqroot.Z.sub.o.sup.2 /M.

Abstract: An N.times.M signal routing matrix has low loss. The N input ports are connected to N input transmission lines, and the M output ports are connected to M output transmission lines. A plurality of interconnects interconnect the input and output transmission lines at their crossing points. The points of connection of the interconnects to any one of the input or output transmission lines are spaced .lambda./2 (or multiples thereof) apart along the transmission line. Each interconnect includes a transmission line at least .lambda./2 long, and each includes a short-circuiting switch arrangement capable of short-circuiting the inteconnecting transmission line at point(s) .lambda./4 (or odd multiples thereof) from the ends of the interconnecting transmission line.

Abstract: The detector is responsive to a modulated intermediate frequency (IF) or radio frequency (RF) signal for producing four sample signals spaced at 90.degree. one-quarter IF (or RF) cycle apart, the first and third sample signals corresponding to the amplitude of the IF signal and its negative value, respectively, the stream of such sample signals corresponding to the inphase component of the IF signal; the fourth and second sample signals corresponding to the amplitude of the IF signal and its negative value, respectively, the stream of such sample signals corresponding to the quadrature component of the IF signal.

Abstract: In a communication system serving a plurality of transmitter-receivers, high capacity is achieved by asynchronous contention access of relatively short reservation request packets, which if successfully transmitted result in the scheduled, noncontention transmission of relatively long message data packets. In a first embodiment, the reservation request packets bear information relating to the duration of the message data packets, so that appropriate message data transmission time may be scheduled. Unsuccessful or colliding reservation request packets are retransmitted. In a second embodiment, the reservation requests packets do not include duration information, and the message data packets have fixed duration. In the second embodiment, collision resolution techniques allow the message data scheduling without retransmission of some colliding reservation request packets.

Abstract: A transformer includes a secondary winding coupled to a load which may be the source and gate of a FET. The primary winding of the transformer is connected to a pair of switching transistors, a first of which couples the winding across B+ during a positive portion of the drive cycle, and a second of which couples a charged capacitor across the primary during a second, negative portion of the drive cycle. The duty cycle defined by the positive and negative portions of the cycle varies. In order to prevent excess current during saturation of the core for duty cycles other than 50%, the capacitor is sized to supply only enough voltage and current to reset the core.

Abstract: An apparatus for breaking the periodicity of the pseudorandom bit stream output from a linear sequence generator. The apparatus includes a ring oscillator which periodically corrupts the sequence of the generator. The level of the supply voltage applied to the logic elements of the ring oscillator is varied over time, thereby altering the oscillator output frequency. In a second embodiment, the temperature of the logic elements of the ring oscillator is varied over time, thereby also altering the oscillator output frequency. A system comprising four of the above-disclosed apparatus having different linear sequences and different corrupting influences, are multiplexed, wherein the multiplexing selection criterion is determined by a logical combination of the four linear sequences.

Abstract: A multi-beam optical recording system includes a semiconductor laser array. The laser beams are expanded via a prism beam expander to have generally circular cross-sections for optimum spot intensity on the recording medium. According to the teaching of the prior art, the average beam angle of incidence on the input prism of the beam expander is the Brewster angle. According to the present invention, means are provided for rotating the beam expander to minimize the variations in spacing between beams, these variations resulting from the magnification distortion of the prisms of the beam expander.

Abstract: A switch-mode power supply includes the series combination of an inductor and a controllable switch adapted to be coupled to a voltage source for producing a succession of increasing and decreasing ramp currents through the inductor. The average value of the ramp currents is controlled by a feedback loop. A second controllable switch arrangement is coupled for causing the current leaving the inductor to recirculate through the inductor during those intervals in which the second switch is conductive. An integrator is coupled to the inductor for integrating ramp current from the inductor during those intervals in which the second switch is nonconductive, for generating load voltage. A second feedback arrangement senses the load voltage and controls the average conduction of the second switch to control the load voltage. In one embodiment, an inverter receives ramp current from the inductor and generates alternating current, which are transformed and rectified before application to the integrator.

Abstract: An array of flared horn antennas is adapted to be fed from circular waveguide. The apertures of the horns are closely spaced. Prior art horns with circular apertures leave gaps in the aperture. The gaps are eliminated, and the gain of the array is increased by about 1/2 dB by tapering the horns from a circular cross-section at the feed end to a hexagonal cross-section at the radiating aperture end.

Abstract: An antenna selectively fed from a square waveguide in one of two orthogonal linear TE.sub.1,0 modes includes a transition between the square waveguide and a larger square horn. A transition arrangement including a plurality of thin conductive elements or vanes is dimensioned and located at the transition to provide a gradual transition between the smaller waveguide dimension and the larger horn dimension in the E plane, and an abrupt transition in the H plane, regardless of the polarization selected. The abrupt transition in the H plane converts some of the TE.sub.1,0 mode energy to the TE.sub.3,0 mode. The radiating aperture is at a predetermined distance from the transition arrangement so that the desired relative phase between the TE.sub.1,0 and TE.sub.3,0 modes may be established. The E-plane aperture distribution is unaffected by the phasing, but the H-plane aperture distribution can be controlled by selection of the appropriate relative phase in order to provide a more linear distribution than TE.sub.

Abstract: A composite amplifier includes a plurality of signal amplifiers. The amplified signals are coupled by transmission lines to node points for combination. In order to achieve a reduction in power below full output power, some of the amplifiers are deenergized. Shorting switches at selected points along the transmission lines are selectively rendered conductive to adjust the impedances to maintain impedance match. Short- or open-circuited transmission lines may also be switched in-circuit to aid in maintaining impedance match.

Abstract: A phase shifter uses a PIN diode or diode pairs operated in a switching mode to switch transmission-line elements for phase-shifting radio frequency or microwave signals. A drive circuit for each diode(s) includes a FET switch controlled by a first level of a bilevel control signal to apply B+ to forward bias the diode(s) with a forward current. When forward biased, the active region of the diode(s) becomes flooded with charge carriers. The first FET switch is turned OFF by a second level of the bilevel control signal, and a second FET switch is turned ON to apply a reverse bias voltage to the diode(s) to render them nonconductive. Before the diode(s) become nonconductive, the excess charge carriers must be swept out of the diode(s). To achieve fast switching, the second FET switch must draw a large current for a short time as the excess charge carriers are removed.

Abstract: A subranging A/D converter generates high and low voltages using first and second DACs. A voltage divider receives the high and low voltages to generate plural reference voltages. A bank of comparators compares the analog voltage which is to be converted to each of the reference voltages, and a clocked logic circuit generates an intermediate digital signal indicative of the analog value relative to the plural reference voltages. The intermediate signal is used to decrement the high voltage and increment the low voltage, so that the reference voltages produced by the voltage divider assume subrange values. The process is repeated for as many clock cycles as is required to converge the high and low voltages to equal the analog voltage.

Abstract: An end effector suitable for manipulating articles such as mail flats is disclosed. This end effector has parallel reciprocating arms having suction cups for gripping the article to be manipulated and mechanical grippers mounted on the arms outboard of the suction cups. These mechanical grippers may be actuated to provide a mechanical grip on a manipulated article in addition to the suction grip.

Abstract: A coupler for extracting energy in the TE.sub.21 mode from a circular waveguide propagating energy in both the TE.sub.11 and TE.sub.21 modes, characterized in that an annular iris on the inner circumference of the waveguide and a longitudinally stepped transition portion of the waveguide define therebetween a TE.sub.21 mode resonant cavity which is coupled via a narrow axially extending rectangular slot contained in the wall portion of the waveguide which defines the cavity. At least one external resonant chamber may be provided on the waveguide through which the TE.sub.21 mode energy is extracted and transmitted to a detector thereof via the slot, which chamber cooperates with the resonant cavity to define a multiple resonant filter for improving the matching to the TE.sub.21 mode while reducing the perturbation to the TE.sub.11 mode.

Abstract: Cost and weight of a heat transfer structure for a space vehicle can be reduced by an arrangement of redundant channels for the flow of coolant to heat radiating panels, micrometeroid resisting bumpers located adjacent the channels for preventing penetration by all but the most energetic micrometeroids, and a sensing and control arrangement for sensing the penetration of a coolant channel for shutting off that channel to prevent loss of coolant.

Abstract: A high data rate optical network data communication system includes a receiver including a photodiode detector, a data slicer and a data decision circuit. A clock recovery arrangement includes an impulse generator coupled to the data slicer to generate impulse signals. The impulse generator includes a high speed ECL NOR gate driven by mutually out-of-phase and relatively delayed data. The impulse signals are applied to ring a coaxial cavity by way of a resistor and an input magnetic coupling loop. The coupling loop allows the cavity to achieve high Q so it will oscillate for a relatively long time, and also provides a path by which bias is applied to the output of the NOR gate to fulfill ECL biasing requirements. The cavity Q is maintained high by coupling signals from the cavity by way of a second magnetic coupling loop. The oscillations are applied by way of a limiter to the data decision circuit.

Abstract: An overdrive control for a GaAs FET power amplifier is provided by a PIN diode attenuator positioned at the input of the FET amplifier where the amount of attenuation is controlled by a control signal derived from the gate current of the following FET amplifier.

Abstract: An unbalanced quarternary phase-shift keying modulator provides relatively higher signal power for one of two signal information channels. The carrier to be modulated is split into two equal-amplitude, equal-phase portions, each of which is applied to a biphase modulator. Each of the information signals is also applied to one of the biphase modulators, for producing two equal-amplitude, phase modulated carriers, each biphase modulated by one of the information signals. The modulated carriers are applied to the ports of a quadrature hybrid coupler which is other than a 3 dB (equal-amplitude) coupler. In one embodiment, the coupler is a 7 dB coupler. The modulated carrier applied to the through port of the coupler appears with reference amplitude and phase at the output of the hybrid. The modulated carrier applied to the other or coupled port appears at the output with relatively reduced amplitude and a relative phase shift. In one embodiment, the phase shift is 90.degree..

Abstract: A set of magnetically responsive vanes are secured for rotation about their mass center of gravity in a given angular spacing. The vanes have corresponding magnetic field producing coils which are in a different angular spacing such that one coil and vane is aligned and a second coil and vane are misaligned. An electrical switch is coupled to the vanes for operation in response to rotation of the vanes. A current applied to one coil aligns its vane thereto and closes the switch. The closed switch applies a load current to a second coil whose vane is misaligned. When an overcurrent occurs, the corresponding resulting field aligns its vane and opens the switch. An off current applied to a coil can align a corresponding vane to also open the switch. The switch and actuator are dynamically balanced so that moments produced by shock and vibration do not operate the actuator vanes or switch.