Abstract: A multiplexed display interference compensation system for minimizing the apparent intensity modulation of an oscilloscope waveform display caused by closely spaced, individually imperceptible interruptions of the waveform required to maintain refreshed readout display is provided. The system includes a charge pump circuit for adding a current pulse to a waveform intensity control signal in response to a control signal from display multiplex control so as to increase the waveform intensity just after the interruption.

Abstract: A dielectric resonator frequency selective network. A frequency selective network for microwave circuits is provided whereby a dielectric resonator is coupled to associated circuitry by input and output coupling loops formed in a single circuit board. The two loops are closely spaced, but partially overlapping at a position such that they are substantially decoupled from one another. A dielectric resonator is placed adjacent one of the loops so as to couple one loop to the other through the resonator and to cause the resonator to operate in its dominant mode. The circuit board is constructed by forming conductors separated by insulating material on a ceramic substrate.

Abstract: An apparatus for time aligning data acquired by one test instrument with corresponding data acquired by another test instrument is disclosed. A set of binary codes, representative of a set of instructions executed by a microprocessor disposed within a user's prototype circuit, are acquired by said one test instrument. With the acquisition of each of said binary codes, a count is developed in a counter indicative of each said acquisition. A multitude of binary data is acquired, independently of the acquisition of the set of binary codes, by said another test instrument, the multitude of binary data being representative of the functions performed by a set of components present within said user's prototype circuit. The binary codes acquired by said one test instrument and the binary data acquired by said another test instrument each have associated therewith a count developed from said counter.

Abstract: A current source circuit includes a first transistor (11) having an output current which is sensed across a resistance connected between the emitter of the first transistor (11) and the negative side of the supply voltage. A series negative feedback loop comprising transistors (13, 15) is connected between the emitter of first transistor (11) and the base of first transistor (11). The transistors (11, 13 and 15) and the other circuit components are selected so as to result in an incremental output resistance approaching that of a cascode current source, while having a voltage drop across the circuit of substantially less than 1 volt.

Abstract: An apparatus for generating a trigger signal having pulses synchronized with selectable angular displacement of a rotating object. The apparatus comprises a position encoder to monitor the rotation of the rotating object and to produce M output signal pulses during each revolution of the object, a frequency multiplier coupled to generate an output signal having a frequency N times the frequency of the position encoder output signal, and a frequency divider coupled to generate a pulsed trigger signal of frequency 1/Mth of the frequency of the frequency multiplier output signal, N being a selected integer and M normally being fixed by the physical contruction. The trigger signal comprises N pulses per revolution of the object and the angular displacement of the rotating object associated with each pulse of the trigger signal is selected by appropriate adjustment of N.

Abstract: Block mode is a method of formatting data when sending it to and from the host computer. Some host computer operating systems make it difficult for the user's program to send or receive the full ASCII character set. The block mode protocol lets you send and receive messages which use the full ASCII character set (including lowercase characters and control characters), even though your host computer's operating system makes it difficult to send and receive certain ASCII characters. (Indeed, even full eight-bit binary data bytes may be sent to or from the terminal in block mode.) This is accomplished by means of a packing scheme, in which messages using the full character set are packed into character strings using a subset of that character set.Also, the block mode protocol provides error detection and automatic retransmission of bad data blocks. This lets you transfer data to and from the terminal, without errors, despite occasional noise on the communications line.

Abstract: An improved bipolar analog switch comprising selectable emitter-coupled pairs of bipolar transistors in combination with an emitter follower output bipolar transistor is provided with means for matching operating characteristics of the selected emitter-coupled pair to eliminate thermal distortion and to provide precise signal replication. Also, a simplified TTL-compatible digital switch control circuit is provided.

Abstract: Apparatus for adjusting the position in two dimensions of a device relative to a support. At least one strut is pivotally connected to the device and is connected to the support. The length of the strut between the device and support is controlled to translate and rotate the device to adjust its position.

Abstract: Spurious responses generated by operation of a spectrum analyzer are eliminated from the analyzer's display by selecting a feature of the displayed signal for testing, adjusting the analyzer controls to display the feature of interest at the center of the screen and with a predetermined span, adjusting the second L.O. frequency by a predetermined amount, and comparing the amplitude of the signal in the analyzer's storage location corresponding to a point on the screen at a predetermined position different from the center of the screen with the amplitude of the signal previously in the storage location corresponding to the center of the screen. If the comparison does not yield substantial equality, the selected feature is eliminated from the display.

Abstract: A paper handling system for a copier is disclosed. A paper sheet is wrapped around a drum of a copier by utilizing the exhaust air flow of a vacuum to lift the paper to the drum and to hold the paper sheet onto the drum. In addition, if a second paper sheet is lifted to the drum in a double pick situation, the second sheet is returned to a paper tray for subsequent copying thereon.

Abstract: An ink cartridge 10 is described with a rigid, hollow housing 12 within which an ink container assembly is positioned. The assembly includes an ink container 16 mounted, as by heat sealing, directly to an ink container support 18. The support 18 is secured by fasteners 24 to a cap 14 of the housing with a gasket 22 and gasket retainer 20 positioned between the support 18 and cap 14. The gasket retainer 20 includes plural gasket retaining projections 104, 150, 152, 156 and an outer peripheral wall 23 which bears against the cap 14 when the ink cartridge is assembled. The gasket support 20 and ink container support 18 cooperatively interfit. To manufacture the ink container assembly, the ink container support 18 is inserted through an opening 74 in a sheet of ink container forming material. The portions 78 of the ink container material bounding the opening are then secured to a planar mounting surface 72 of the ink container support 18.

Abstract: A constant amplitude, variable-bandwidth filter is provided having a variable resistor and a high-Q passive filter cascaded between a pair of amplifiers. The input amplifier having a low output impedance and the output amplifier having a low input impedance. As the resistance of the variable resistor is varied, the Q of the system varies and thus its bandwidth. The gain of the system also varies as the variable resistor is varied. To compensate for the gain variation, a current, equivalent to the value of the output voltage of the input amplifier divided by the value of the equivalent series resistance of the high-Q passive filter, is inserted at the node where the variable resistor and the high-Q passive filter are coupled one to the other. This results in a constant current at resonance being conducted by the high-Q passive filter, independent of the selected overall bandwidth of the filter.

Abstract: An oscillographic device receives plural vertical inputs which are multiplexed to provide plural traces by means of the same electron beam. Switching times of the multiplexer are varied during the display to avoid gaps in waveform presentation when the period of the device's horizontal sweep is a near multiple of the switching period of the multiplexer.

Abstract: A liquid crystal cell (100) includes a chiral additive in the liquid crystal material (106) to operate the cell as a rapid starting, high-speed variable optical retarder. The cell is fabricated so that the surface noncontacting directors (116 and 118) of the opposed surfaces of the director alignment layers (112 and 112') of the electrode structures (102 and 104) are tilt-biased in opposite directions. This surface contacting director configuration induces rapid surface noncontacting director (120a, 120b, 120c, 120d, 120e) relaxation without optical bounce when the cell is switched from the field aligned ("ON") state to the partly relaxed ("OFF") state. The chiral additive prevents an inactive cell from relaxing to the splayed topological state, thereby enabling switching operation without a warm-up delay and preventing the surface of the cell from having a mottled appearance when it remains unused.

Abstract: A separator for separating adjacent transparencies in a stack of transparencies, where the separator is characterized by enhanced permeability due either to the intrinsic material from which it is made, or due to a plurality of apertures, holes, perforations or the like provided through its surface. In use, the separator adheres to the transparency due to suction created by a vacuum transport mechanism of the reproduction machine such that the transparency and separator move as a unit along a paper path of a reproduction machine.

Abstract: A method of fabricating multilayer printed circuit boards using polymer thick film technology is disclosed which utilizes photoimageable dielectric material between conductive polymer thick film layers and which is capable of producing extremely small and uniformly-sized vias.

Abstract: Disclosed herein is a system for addressing a memory pack having a plurality of memory chips such as RAMs or ROMs. Each memory chip receives address signals and a chip enable signal. A chip selector generates the chip enable signal in response to a feedback signal from the memory pack provided in response to the memory address lines. Since each memory pack excludes the chip selector circuitry, the memory packs can be made smaller in size. The memory packs are in effect self-configuring since they control the feedback of the address signals to the chip selector which generates the chip enable signals. Many types and capacities of memory packs can be mixed in the system since the pack determines the memory address space in which it resides.

Abstract: A programmable oscillator includes first and second transistors having their emitters coupled by a capacitor, and a pair of current sources coupling respective transistors to ground. A switching means is provided having a first state coupling the collector of the first transistor to the base of the second transistor and coupling the collector of the second transistor to the base of the first transistor, and a second state coupling the collectors of the first and second transistors to ground such that when the switching means is in the first state, the first and second transistors switch on and off in alternating fashion, and when the switching means is in the second state the first and second transistors remain on continuously.

Abstract: A method and apparatus for automatically detecting peak values of an applied unknown electrical signal employ a binary search technique in which a digital signal is converted to analog reference voltage levels one bit at a time from the most significant bit to the least significant bit to be compared with the unknown signal until finally a digital signal is produced which corresponds to a peak value. By selecting and controlling the comparator slope, both positive and negative peaks may be detected. The search for positive and negative peaks of signals occurring in one or more signal channels may be interleaved to decrease total detection time. From the detected values, a triggering voltage level may be arithmetically computed.

Abstract: A compensation circuit is described for use in a line scan type recording apparatus where an electron beam is scanned on the face of a fiber optic cathode-ray tube (FOCRT) in synchronization with a movable recharging medium. The compensation circuit includes a charge pump circuit, an integrator circuit, and a current source. The charge pump circuit draws a constant charge from the integrator circuit in response to a repetitive series of stepper pulse corresponding to the velocity changes in the recording medium. The current source generates a constant current that flows into the integrator circuit and is equal to the average DC current flowing out of the integrator circuit via the charge pump circuit. The output voltage of the integrator circuit is used for controlling the vertical displacement of the electron beam of the FOCRT in synchronization with the movable recording medium.