Abstract: A test clip and grounding adapter assembly comprises a conventional integrated circuit test clip of a type having parallel arrays of signal conductors retained in a pair of molded plastic arms biased closed on the leads of a unit under test.An adaptor in accordance with the invention having twice as many conductors as the test clip interconnects the test clip and a ribbon cable. The additional conductors within the adaptor interposed with the signal conductors in the clip are grounded to electrically shield the signal wires.

Abstract: Circuit faults in an electronic system are isolated by a programmed computer that guides a technician node-by-node on a unit under test (UUT), such as a circuit board, to the source of a failure. Stimulus pattern signals are applied to the circuit, and responses at the circuit nodes are made by a measurement probe under the hand of the technician. As each node is probed, a stimulus pattern signal tailored for testing that node is applied to the UUT. The measured response is compared to a predetermined response corresponding to an operational UUT to generate a failure accusation or recommend the next node to be probed. The computer is programmed to expedite the search for the source of the failure by displaying to the technician clues which define the circuit nodes most apt to be defective as a result of preliminary functional testing of the UUT.

Abstract: To eliminate crosstalk between successive measurements of an integrating analog-to-digital converter having MOS linear amplifiers (16) that as a result of ion distribution shift in its input devices gate oxide (24) tends to retain a conversion residue (R), at least one "dummy" conversion cycle (38) is executed prior to each input signal measurement. The "dummy" conversion cycle (38) reduces the residue (R) by moving input gate ions into stable positions corresponding to the magnitude of the input signal to be next measured.

Abstract: The invention comprises first and second wiring carriers surrounded and separated by shielding means, conductive lines on said carriers being electrically joined by means of a projection (pin) and socket. The projection extends coaxially through a hole in the shielding means.

Abstract: Fine particles, preferably of brown alumina (approximately 96% Al.sub.2 O.sub.3), are disposed between closely spaced and normally parallel surfaces of two adjacent transparent layers, such as are typically found in a touch sensitive overlay (TSO). The particles are preferably of a size within the range 3-100 microns, and are distributed in a density preferably in the range 300-3,000 particles per square inch, so that the larger particles are in simultaneous contact with both the parallel surfaces. Local pressure on a TSO panel with this distribution of particles of non-uniform size allows operation of the panel without the generation of distracting Newton rings between the surfaces contacting the particles. These particles may be conveniently sprayed onto either of the parallel surfaces in suspension with a fluid carrier that evaporates to leave the particles adhering to the sprayed surface.

Abstract: A test voltage is applied through an array of "guarded" switches (58) to selected ones of a plurality of components to be measured. Each switch (58) comprises first and second input terminals (69, 72), first and second output terminals (70, 74), and a wire (76) interconnecting the second input and second output terminals (72, 74). The switch (58) is operable selectively in a first state interconnecting its first input and output terminals (69, 70) and in a second state interconnecting the second input and output terminals (72, 74). A buffer amplifier (88) couples the input signal from the first input terminal (69) to the wire (76) interconnecting the second and output terminals (72, 74) of the switch (58) as a "guard voltage" to prevent loading of the input signal by leakage resistances within the switch.

Abstract: A method of manufacturing a circuit board from a copper clad board comprises the steps of designing a circuit configuration of the circuit board on a computer-aided design system and then determining a desired circuit configuration outline on the computer-aided design system from the circuit configuration. The desired circuit configuration outline is provided to a computer-aided machining system which controls a laser, milling machine and the like to remove conductive material along the outline, leaving conductive material formed adjacent the removed material as the circuit configuration.

Abstract: An amplifying system and method produces a substantial reduction in the D.C. and even-order harmonics in an output signal by employing a first inverting amplifying stage cascaded with an attenuating stage which is cascaded with a second inverting amplifying stage. The electrical characteristics of each of the two inverting amplifying stages are substantially the same. The gain, in dB, exhibited by each of the amplifying stages is substantially equal to the attenuation loss, in dB, produced by the attenuator stage. Conventional components and fabrication techniques allow substantial attenuation of the D.C. and even-order harmonic components produced by the nonlinearities in the active devices of the amplifiers as compared to a single amplifier case producing the same gain A.

Abstract: The storage units and the output of an averaging type recursive or non-recursive digital filter are modified by input signal changes greater than a predetermined amount indicative of a step change to provide a rapid step response characteristic.

Abstract: A method of making a molded circuit board includes forming a polymer base with a channel and an intersecting through-hole. The base is conductively coated by means of vacuum deposition to establish a circuit line. After the conductive coating is removed everywhere except the channel and the through-hole, a further conductive material is provided on the coating. The base is subsequently stress relieved and planarized.

Abstract: In a dual slope analog to digital converter, the input amplifier has an input selectively connectable to an unknown analog source or a known opposite polarity analog source. The output of the amplifier is directly or indirectly connectable to its other input to change the gain of the output. A microprocessor controls the converter to sequentially connect the unknown analog source, instantaneously change the output connection to change gain where appropriate, and connect the known analog source.

Abstract: A regulated voltage supply (10) for delivering a substantially constant voltage to a load (12) having a regulator (24) for controlling a raw voltage supply (22) to deliver that constant potential, wherein the supply includes sense leads (28 and 30) between the load and the regulator for monitoring load voltage, provided with a sense current cancellation circuit (30) for nulling sense current and preventing it from flowing through the sense leads; in a preferred implementation, including voltage-to-current converters (42 and 44) bridging respectively the output terminals (14 and 16) and the sense terminals (32 and 34), it provides a cancellation current equal in magnitude and opposite in direction to the sense current.

Abstract: The ladder network of a recirculation of remainder analog to digital converter has a voltage source that is regulated by a transistor and Zener diode together with feedback circuitry responsive to the regulated output voltage. Current through the circuit is controlled by feedback to establish equal and opposite temperature coefficients in the transistor and Zener diode of the regulator. The temperature stabilized voltage regulator produced thereby eliminates any requirement for trimmer potentiometers.

Abstract: A three modulus prescaler for a phase-locked loop frequency synthesizer includes a N.sub.0 modulus prescaler inputting into a divide-by-two circuit. A microprocessor and internal logic control a three modulus prescaler synchronizer to receive signals from the divide-by-two circuit and output control commands to the N.sub.0 modulus prescaler so as to cause the N.sub.0 modulus prescaler to divide solely by a first or second modulus, or alternately between said first and second modulus, between output pulses of the divide-by-two circuit to extend the synthesizer's bandwidth.

Abstract: A touch-sensitive overlay (20) for cooperative, optically proximate engagement with a visual display (22) of luminous character information (38) latently occupying one or more of a plurality of character locations (26) defined with a position-multiplexed coordinate array one from another, is comprised of a mask (44) of a photoreactive transducer (52) having at least one photoelectric parameter which varies as a function of incident light from the display of character information striking the transducer, and a signal circuit element (92) responsive to a variation in the photoelectric parameter in communication with the mask for developing a characteristic logic pulse indicative of the position of one or more character locations within the array upon a touch thereof and the coincident presence of character information thereat (48).