Abstract: An apparatus for reconfiguring power comprises a four-bridge network. Each bridge is controlled by complementary switch pairs driven by three-state control signals. One state provides for system shut-down and the other states provide for bridge operation. Reconfiguration is achieved by retrieving one of a plurality of patterns of switch signals to produce a desired output. The switch patterns are changed to maintain a desired output for a varying input.

Abstract: Two hooks are adjustable in position along a cylindrical bar for engaging operating elements in a vehicle, thereby preventing operation of the vehicle. One hook is fixed to an end of the bar. The other hook includes a yoke having arm ends pivotable about the bar. A lock body is captured between the yoke arm ends for pivoting about the bar. A spring wound under tension on the bar has one end attached to the yoke and the other end attached to the lock body. Pivoting of the lock body relative to the yoke, releases the spring, allowing sliding of the hook along the bar. A lock is mounted on the lock body for securing the lock body in a position in which the spring is under tension on the bar, thereby preventing movement of the hook along the bar.

Abstract: A print medium sheet feeding system for an ink jet printer having a print head with a planar array of jets is provided by clamping the leading edge of a paper after it is passed through a printing zone to a rotating assembly of parallel disks. The sheet is pulled through the printing zone by rotating the disk with the clamp being carried with the rotating drum. A platen may be provided which has a flat surface in the printing zone forming a tangent to the outer surface of the rotating disks. Alternatively, the platen may be removed and the sheet held in tension between the clamp and a nip region formed by a spring plate held against a restraining plate. In an alternative embodiment, the sheet is initially clamped against the drum by the combination of a lever arm which is selectively engageable with the drum for rotation therewith and an attached actuating arm having a plate which secures a sheet to the drum surface.

Abstract: A monitoring and alarm system for a radio frequency microwave communications repeater unit. A plurality of signals representative of the status of a corresponding plurality of operating conditions of the repeater unit are simultaneously generated. The signals are time multiplexed to form a combined signal. The combined signal is encoded to form a digital signal of frames of data having a frequency substantially less than the communication signal carrier frequency and preferably less than the communication modulating signal frequency, with a frame being formed of data from each of the status signals. A variable attenuator is responsive to the digital signal for varying the level of the communication signal proportionally with the value of the digital signal. The level-varied communication signal is then retransmitted.

Abstract: A motion controller for the head carriage of an ink jet printer comprises a target signal generator providing constant velocity reference input to a servo loop controller. Also, two levels of current are applied to the drive motor during direction reversal, a lower one during deceleration of the carriage, and a higher one during acceleration of the carriage. The timing of the two current levels is determined by inputting a rectified velocity signal into a slope detector. A comparator converts the output of the slope detector into a binary signal for controlling the motor current level.

Abstract: A loaded Lange coupler embodied as an integrated circuit includes interdigitated strip conductors and lumped-element capacitors. The two interdigitated strip conductors couple the input and direct ports together, and the isolated and coupled ports together. A capacitor extends between each of the input and coupled ports and the isolated and direct ports. Further, a capacitor extends between each of the midpoints of the strip conductors and ground. This coupler is formed as an integrated circuit in which the current-to-ground capacitors are substantially in line between opposite port pairs and the strip conductors extend around these capacitors.

Abstract: A video cassette recorder plays an audio/video tape prerecorded with a video signal, three voice signals and three audio control signals. One of the voice signals is modulated with a carrier higher in frequency than the other voice signals for recording. The video image is displayed on a television monitor. The audio signals are coupled to a control unit which broadcasts one of the voice signals and transmits the other two with associated control signals to remotely located dolls. The dolls broadcast the voice signals according to the corresponding control signals. Hand-held switch units allow individuals to preempt broadcasting by the dolls to permit the individuals to interject their own vocal responses.

Abstract: A control topology for a servo motor carriage drive includes a strain gauge coupling the carriage to a motor-driven belt to provide a signal representative of the flexure of the belt. A velocity signal is taken from a linear encoder on the carriage. These signals are used in inner and outer feedback loops for controlling the velocity of the carriage as it travels along a predetermined path.

Abstract: A push-pull monolithic active isloator having a pair of MESFETs in common-gate and common-drain (source follower), parallel configuration. These two FETs are the same size and a diode is inserted between the gate of the source follower and the source of the common-gate FET. A D.C. blocking capacitor is included at the output. Another FET is coupled between the input and ground and responsive to a control signal to vary the current in a biasing resistor between the drain and gate of the source follower.

Abstract: A sample-and-hold circuit for sampling a time-varying signal comprises a main sample-and-hold subcircuit extending between input and output terminals and an auxiliary sample-and-hold subcircuit extending between the input terminal and a portion of the main subcircuit. Each sample-and-hold subcircuit comprises an input buffer amplifier, a diode-bridge switch responsive to a control signal and coupled to the input buffer amplifier, a charge-holding capacitor coupled to the switch, and an output buffer amplifier coupled to the capacitor. The output of the auxiliary output amplifier is further coupled to the main switch and the output of the main output amplifier is coupled to the output terminal. A generator generates the control signal for controlling the switches such that the same part of the time-varying signal passing through the main and auxiliary subcircuits is sampled.

Abstract: A device for generating a digitizing pulse for sampling an analog video signal includes a phaes-locked-loop (PLL) circuit and a phase offset circuit. The PLL circuit generates a correction pulse required to bring an output signal of digitizing pulses in phase with a reference horizontal sync signal. The phase offset circuit includes a digital memory which stores a digital number representative of a fraction of a pixel pulse that is desired as phase offset of the digitizing pulse. This fraction is converted into an offset current pulse having a duration equal to the duration of a pixel pulse and an amplitude that is the fraction of a maximum amplitude. The offset current is added to the PLL correction current for generating an output signal of digitizing pulses having the desired phase offset relative to the pixel pulses.

Abstract: A differential amplifier in the form of a Gilbert gain cell is controlled by a pair of input currents applied to a pair of differentially coupled transistor pairs. A digital signal is generated and input into a CMOS digital-to-analog converter (DAC). The DAC outputs a pair of currents on conductors which are maintained at virtual ground by the use of a current mirror and an operational amplifier. The control signals applied to the differentially coupled transistor pairs are generated as base currents of transistors conducting the DAC output currents.

Abstract: A state element having a pair of parallel-connected, inversely-enabled latches forms the basic state-machine building block. A flip-latch is formed by combining this basic element with a multiplexer for selectively outputting alternate outputs of the latches. A litch-latch is formed by using the basic element alone with the two inputs fed from one of a pair of identical logic elements and feeding back the output from each latch to the logic element from which the input is not received. Other outputs of the logic elements are input into a multiplexer for alternately selecting the outputs from the respective logic elements to be the state machine output. These state elements function similarly to a flip-flop but generally produce less propagation delay and require a lower clocking signal frequency for a given state frequency.

Abstract: A sample and hold circuit made entirely of NPN transistors, capacitors and resistors uses double emitter-follower transistors for gating an input signal onto a charging capacitor. A transistor connected in parallel to the first of the emitter-follower transistors is controlled to conduct blow-by current away from the second emitter-follower transistor in the hold state. A step voltage is applied to the charge capacitor in the hold state to prevent turn on of the emitter-follower transistors. The circuit is configured with complementary components so that a differential output signal eliminating the step voltage is provided.

Abstract: A circuit for detecting positive and negative pulses of a predetermined maximum duration of an input signal includes a first monostable circuit for generating a first pulse having a duration equal to the predetermined maximum duration when a positive-going edge of a pulse occurs in the input signal. A second monostable circuit is provided for generating a second pulse also having a duration equal to the predetermined maximum duration when a negative-going edge of a pulse occurs in the input signal. An AND gate is coupled to the output of the first and second monostable circuits for generating a signal having a third pulse equal to the period of time both of the first and second pulses occur simultaneously. A flip-flop is coupled to the output of the AND gate for generating an output signal of a first logic state when the third pulse is generated.

Abstract: A rotary pulse generator is disclosed which generally includes a wheel rotatable about an axis. The wheel has a plurality of protrusions which deflect a piezoelectric element in a deflection zone. Several embodiments are shown. The various features include a thumbwheel in which the turning surface has teeth on it serving as the protrusions, a thumbwheel in which the teeth are directed radially inwardly, a push/pull knob which places the wheel in alignment with a selected one of three piezoelectric elements, and a wheel held in selected positions by an indent/detent mechanism with rods extending out of the side of the wheel to deflect the piezoelectric element. Yet another embodiment provides for the combination of linear and rotary pulse generation. Another form provides four sets of indicator locations with a location from each of the sets forming an aligned row of indicator locations.

Abstract: A monostable circuit responsive conditionally to a circuit input signal for generating a circuit output signal having a pulse of a predetermined duration includes an AND gate having two input ports and an output port. ONe of the input ports is coupled to the circuit input signal and inverts that signal. The other of the input ports is coupled to the circuit output signal. A reset OR gate receives a reset signal and the output of the AND gate. When the reset signal is low, the reset OR gate outputs the output of the AND gate, thus enabling the curcuit. The output of the reset OR gate also goes to a ramp generator having a ramp capacitor, the charging current to which is provided by a current driver. The reference voltage for a comparator is provided by circuitry identical to that associated with the ramp capacitor except that an intermediate bias reference is applied to it. This bias reference is compensated for the effect temperature changes on the circuit.

Abstract: Tape guides of a magnetic tape transport machine are controlled during movement by sensing the position of the member as it moves along a defined path in varying velocity corresponding to the position. The member is initially accelerated at a selected rate to a maximum velocity which is then maintained until a distance close to the end position is reached. Velocity is then reduced at a selected rate until another position closer to the end position is reached. At this position a final velocity is maintained until the end is reached. A determination is made of how closely the second distance from the end coincided with reaching the final velocity. The length of the first distance from the end position is adjusted to reduce the difference between the coincidence of reaching the second distance and the final velocity. Further, the sensed final position of the member is retained as the target final position for the subsequent operation.

Abstract: The disclosed coupler is in a spiral form having approximately 11/4 turns and a length of just over 1/4 wavelength of a designed frequency. The coil includes an interdigitated section with two conductor portions for each conductor. In the overlapped turn portion, the inner conductors are narrower than the outer conductor. Further, conductor pads are disposed adjacent the coupler conductors for connection to associated couplers to vary the bandwidth of the coupler.

Abstract: A split band filtering scheme to reduce adjacent band interference in a communications network, such as a cellular mobile radio system, is disclosed. A repeater, interposed between a base or cell site and a mobile/portable radio, includes a down converter for converting a system operating frequency to a lower frequency signal. The lower frequency signal represents a communications band. The signal is presented to a split band filter having a narrow passband with steep skirts. The processed signal is coupled to an up converter where it is restored to the system operating frequency. In this way, the passband of the repeater is restricted to that of the desired communications band and adjacent band interference is reduced or eliminated.