Abstract: A receiver for data encoded as a series of symbols, each including a plurality of components such as the I and Q components of 16-QAM symbols or other multi-value multi-phase system. Each component denotes values for a plurality of bits. Probability calculation circuits 111-1 through 111-16 use the values of the components constituting each received symbol to calculate the probability that each one of the possible symbols was transmitted and received. Metric calculation circuits 112-1 through 112-4 calculate a bit metric for each bit denoted by the symbol. The bit metric represents the probability that the bit having a specified value was transmitted. The bit metric may be calculated by adding the probabilities calculated by the probability calculation for those possible symbols having a component denoting the specified value of the bit. For example, the sum of the probabilities of all symbols denoting a first bit value of zero gives the probability that a zero bit value was transmitted and received.

Abstract: A probe assembly for testing at least partially conductive elements has a dielectric base plate, a plurality of conductive supports on the base plate generally insulated from each other thereby, and each having a forwardly open socket having a forwardly concave socket surface, and a plurality of conductive contact rods, each having a substantially part-spherical rear ball end having an outer surface, and resting in a respective one of the sockets, and a forwardly directed front test end. According to the invention one of the surfaces is formed with at least one edge engaging only in line contact with the other surface. Thus, when the tips are engaged with conductive regions of an element to be tested, electrical connection can be made at the region of line contact between the contact rod and support.

Abstract: The system includes a digital integrator having a plurality of digital stages operable to store a numerical value in binary digital form which is indicative of state of charge. A switching circuit is provided for generating a series of voltage pulses on a single output line with each pulse corresponding in length to the binary digital value stored in the integrator to provide a time based resultant indication of the stored binary digital value. A filtering means is included to provide a substantially smooth analog output voltage having an amplitude corresponding to the summation of the pulses.The system preferably includes a delayed high voltage reset feature to set the integrator to a full charge state in response to voltage levels accompanying charging of the battery.

Abstract: An RF wattmeter is disclosed of the type using an "insertion-type" pick-up element to produce a voltage wave signal corresponding to the measured power in the coaxial transmission line. The induction loop in the pick-up element is connected to a principal detector, and a secondary detector is connected in opposition to the principal detector. Both detectors are located in close proximity to each other and are subject to the same thermal environment. A sine wave generator supplies a wave signal to the secondary detector in opposition to the wave signal supplied to the principal detector from the inductive loop. The d.c. portion of the resulting signal representing the difference between the opposed signals is integrated, and the integrated output is used as the amplitude in the generated sine wave. When the circuit is in balance, the integrated output matches the amplitude of the inductive wave form and can be used as an output indicating measured power in the coaxial transmission line.

Abstract: An in-circuit test apparatus having a vacuum chamber between a top plate and a base plate. The apparatus has an adjustable bearing block assembly located at each quandrant to provide a precision alignment between the top plate and the base plate. A continuous double-hollow tube is located in a uniform groove in the base plate and forms a seal when held captive between the top plate and the base plate. A plurality of spring probe pressure pins are mounted within the chamber. The pins project through drilled individual access ports in the top plate and make electrical contact with a printed circuit board under test when the top plate collapses under a vacuum.

Abstract: In order to determine the overall phase and amplitude distortion undergone by signals sent over a transmission channel, a pulse sequence generated at one end of the transmission channel is received at its other end at a first and a second input of a measuring instrument including, downstream of a receiving stage connected to the second input, regenerating circuitry for producing replicas of the original pulses. The latter are fed, along with the received distorted pulses, to a phase and amplitude comparator working into a spectral analyzer which displays the spectral-density difference between a received pulse and a replica of the corresponding transmitted pulse. The second input of the instrument may be connected to the output side or to the input side of an equalizer which supplies the received pulses to the first input thereof and whose parameters are to be adjusted on the basis of the measurements made.

Abstract: A system for measuring power in an electrical distribution circuit having at least three wires includes a Hall-effect generator directly coupled to one of the live wires of the circuit and current transformers coupled to the other live wires of the circuit. The output of each current transformer is magnetically linked to the Hall-effect generator. The excitation current for the Hall-effect generator is derived from the line potential between the live wires. The Hall-effect generator acts to produce an output whose magnitude is directly proportional to the product of the vector sums of the currents flowing in the live wires and the potential between the live wires. This power indicative output may be accumulated to produce an indication of energy consumed by a load connected to the live wires. A high frequency A.C. bias is applied to the Hall generator in order to linearize the output of the generator.

Abstract: Circuitry for use in a voltage measurement and display device provides automatic function change for measurement of AC or DC voltages. Voltage measurement in a predetermined mode (DC, for example), is assumed. Upon detection of an input voltage component exceeding a predetermined threshold of the other mode, (AC, for example), the measurement function is changed to that other mode. Upon detection of a component in the other mode, in a range between the predetermined threshold and a second (preferably lower) threshold, an annunciator is activated to alert the user to the presence of the other mode (AC) voltage, for manual activation of a function-selecting switch if desired. Thus, in a specific embodiment, automatic function changeover is provided upon detection of AC components exceeding a predetermined threshold, along with activation of an AC annunciator.

Abstract: A testing apparatus of semiconductor wafers includes a base plate and a probe card including probe needles, wherein the probe card is detachably affixed to the base plate under air suction, which is derived from a vacuum produced in an airtightly sealed space provided between the base plate and the probe card.

Abstract: This interface permits the testing of high speed semiconductor devices (room-temperature chips) by a Josephson junction sampling device (cryogenic chip) without intolerable loss of resolution. The interface comprises a quartz pass-through plug which includes a planar transmission line interconnecting a first chip station, where the cryogenic chip is mounted, and a second chip station, where the semiconductor chip to be tested is temporarily mounted. The pass-through plug has a cemented long half-cylindrical portion and short half-cylindrical portion. The long portion carries the planar transmission line, the ends of which form the first and second chip mounting stations. The short portion completes the cylinder with the long portion for part of its length, where a seal can be achieved, but does not extend over the chip mounting stations. Sealing is by epoxy cement. The pass-through plug is sealed in place in a flange mounted to the chamber wall.