Abstract: In a heterodyning arrangement to enable frequency response testing of a system at a high frequency F using a digital correlator capable of operation at a lower frequency F/h, an offset signal is generated at a frequency F(h-1)/h and multiplied with the output signal of the system under test. Two heterodynes result: a wanted signal at a frequency F/h, and an unwanted image signal at F(2h-1)/h. The value of h is selectable independently of a divisor N which controls derivation of the test frequency F from a frequency synthesizer operating at a frequency NF. Thus the frequency of the image signal can be arranged to avoid spurious non-zero responses in the digital correlation process at frequencies related to N.

Abstract: A solid-state demand register is described for determining the maximum electrical-power demand made on an electric utility by a load. The register, which employs a microprocessor, provides noncumulative, cumulative, and continuous-cumulative electrical-power demand measurement capabilities. The microprocessor, operating under a control program stored in a read-only memory, employs computing constants and generates computed results. A nonvolatile read/write memory, which stores the computing constants and computing results, is of the type that retains stored data even when deenergized. These constants and results can be visually displayed by an optoelectronic display. Error detection and correction of data are performed by the programmed microprocessor by means of an eight-bit Hamming code.

Abstract: A monostable circuit of a voltage-to-frequency converter supplies feedback pulses to balance the input signal to a first integrator. These same pulses are supplied to a second integrator where they are compared with reference pulses from a crystal-controlled clock. Any drift in the pulse-width of the feedback pulses is corrected by a control signal applied to the monostable circuit by the second integrator to vary its quasi-stable period appropriately. Thus the precision of the converter is improved without disturbing its asynchronous properties.

Abstract: A camera contains a row of diodes sensitive to infrared radiation and mounted on a turntable for rotation about the optical axis of the camera. The signals from the diodes provide a temperature profile of a band across the width of a strip of hot rolled steel moving in a direction orthogonal to the optical axis and to the length of the row of diodes. Since the diodes are low accuracy devices, their measurements are compensated by normalizing co-efficients derived by comparison with the signal provided by an optical pyrometer viewing the central part of the steel strip in the region of the optical axis. To enable all diodes to be calibrated, calibration is effected with the turntable rotated 90.degree. to align all the diodes with the central part of the strip as viewed by the pyrometer. The camera may be mounted on one arm of a C-frame having X-ray tubes in an arm and X-ray detectors in the other arm for the purpose of measuring the thickness profile of the strip in known way.

Abstract: In an electrical connection system between a payment card (10) including an integrated memory circuit (11), and an information transfer apparatus (15) for reading and writing data in the memory circuit, terminals (14) of the card (10) are covered with a protective layer of a plastic material (13) which is perforable and recoverable (self-healing), and the transfer apparatus is provided, for each terminal, with a projection (16) of hard metal ending at a point (17) to be urged with a defined force on to the corresponding terminal in the card through the protective layer.

Abstract: Departure of a logic signal from the ranges of signal values corresponding to defined logic levels is monitored by comparing the logic signal with the boundary values of these ranges. Provided the logic signal between transitions is below the lower threshold (14) or above the upper threshold (12), a NOR gate (16) and a D-type bistable circuit (18) open an AND gate (22) to enable a counter (24) to count 10 MHz clock pulses. If the logic signal is between the thresholds, the AND gate disables the counter. The four most significant digits of the total number of clock pulses actually counted after 1,000,000 have been supplied is displayed, giving an indication of the percentage of time for which the logic signal has a value corresponding to a defined logic level. As an alternative, the output signal of the NOR gate (16) can be inverted (26) and supplied to a moving-coil or digital voltmeter (30).

Abstract: A measurement shunt comprises a resistance provided with first and second voltage terminals and intended to provide a voltage representative of an electric current passing through it, and an inductance connected to at least the first of said voltage terminals to produce between first and second measurement terminals a voltage free of error voltages induced in said resistance, even in the presence of a variable magnetic field. The resistance is essentially constituted by a plate (12) of electrically conductive material, the first and second voltage terminals (26,28) are disposed on the same edge of the plate at spaced apart points thereon, and the inductance comprises at least one open loop (36a) at least partly formed from an electrically conductive material extending from its first and second ends respectively disposed in the vicinity of the first and second voltage terminals, towards the interior of the surface of the plate in a plane having, at least approximately the same direction as the plate.

Abstract: A keyboard has tactile-feel keys (64-70) each with a grounded terminal (78) under an insulated touchable terminal (88) supplied with a square wave signal.Touching a key increases the capacitive delay of the square wave signal on that key, so it is retarded relative to first delayed clock pulse which then resets a bistable circuit (142) to stop a counter (152), which controls scanning of the keys, at a value indentifying the touched key. This enables selection of the touched key to be verified, for example on an associated video display, whereafter the key can be pressed to actuate it, thereby establishing contact between its terminals. The resulting grounding of the touchable terminal suppresses the square wave signal, resetting another bistable circuit (172) in response to another, more delayed, clock pulse to generate a signal indicating that the desired key function is to be implemented.

Abstract: In a tape transport apparatus comprising notably a floating roller (12) tangent to reels (5, 6), and an elastic endless belt (11) extending between the floating roller (12) and the reels (5, 6) to form a first loop (11a) surrounding the floating roller (12) and a second loop (11b) engaging on an arc of the periphery of each of the reels (5, 6) to maintain the tension of the accessible portion of the tape (7), this second loop (11b) extending around at least one return roller (13, 14), the invention provides that at least return roller (14) is directly driven by drive means (18, 19), whereby the peripheral speed of the driven return roller (14) and the peripheral speed of the floating roller (12) are maintained in a ratio slightly greater than 1, so as to ensure better tensioning of the tape on the take-up reel.

Abstract: An X-ray or gamma-ray scintillation crystal used in a radiation-type thickness gauge is calibrated by irradiating the scintillation crystal at a high intensity and then abruptly lowering the intensity to a low level (e.g. 1/100 the high intensity level). The nonlinear response of the crystal due to after-glow and hysteresis is periodically measured and correlated with an ideal (e.g. linear) response function. The radiation level is then increased to its former high intensity and periodic measurements are made of the nonlinear response of the crystal. The correlated values are stored, for example, in a computer memory as a table of time dependent correction factors. The stored values are used to correlate a measured signal from the scintillation crystal regardless of the radiation intensity and the hysteresis of the crystal and without having to wait for the "afterglow" to disappear in order to make subsequent measurements.

Abstract: To mimimize the weight of a magnetic tape recorder chassis and cabinet assembly, a wire frame chassis (18) carrying printed circuit board guides (20) and connectors (22) is mounted to one side of a sand cast bezel (24), and polyurethane wall panels (16) are secured to the wire frame. A cabinet cover and underlying tape transport assembly are hinged to the bezel to enable pivoting away from the wire frame, exposing circuit boards for servicing. The "open air flow" characteristic of the wire frame chassis (18) helps cool critical electrical components.

Abstract: A visually and electronically readable motor driven register has a plurality of dependently rotatable, coaxial, incrementally positionable, number wheels which each carry a movable electrode fixed in a predetermined position relative to the numbers on each wheel. Adjacent each movable electrode is inserted a fixed plate which carries a plurality of stationary electrodes, each corresponding to a number on the wheel and disposed circumferentially around a stationary main electrode which is capacitively coupled to the movable electrode. When a number on a wheel is visually readable, the movable electrode will be positioned so as to be capacitively coupled only to the stationary electrode corresponding to the readable number. A microprocessor provides pulses sequentially to the stationary electrodes of each wheel, and checks for a coincident processed output from the main electrode of the first wheel.

Abstract: A gain switching apparatus for a signal is controlled by a switching function formed as a function of the signal. The apparatus is provided with a circuit for reducing errors due to common frequency components in the switching function and in the signal being switched thereby. In order to reduce DC error resulting from multiplication of the switching function by a parameter representing the switched signal, the common frequency component of the switching function is substantially eliminated and replaced by a component at a frequency which is a multiple of the common frequency. A simplified logic circuit is provided to perform the frequency multiplication and the resultant error reduction.

Abstract: A power factor capacitor made with case to housing insulation of thin electrical grade polypropylene in multilayers to greatly exceed basic impulse level voltage test requirements.

Abstract: A microprocessor is programmed to perform the DFT on data points read out from and written back into a RAM. In each of a plurality of levels of the transform the points are read out in small groups, subjected to a discrete Fourier transform and written back into different addresses in order to avoid jumbling the order of the points in the ultimate output. The read-out and write-in addresses are read out of a PROM in sequence for each group and added to a base address in a latch. A -N latch, adder and multiplexer ensure that the addition is modulo N. After each group, the base address is changed to a new value by adding another value read out of the PROM and all addresses are worked through in this way in each level. At the start of each level the microprocessor puts the correct PROM start address in a latch and the number of groups (m) in a counter which is decremented to count off the groups and signal the end of a level.

Abstract: The invention enables a logarithmic plot to be generated for values pertaining to uniformly spaced sampling points of a frequency axis, for example, such as the values provided by a discrete Fourier transform processor, while utilizing a conventional display device with a linear time base. To this end the array of input values provided by the processor is converted in a further processor to values corresponding to points uniformly spaced along a logarithmic frequency axis. If points on the logarithmic and linear axis are indexed by values x and y respectively, the y values (in general non integral) corresponding to x-1/2 and x+1/2 are calculated, the corresponding integral values of y are ascertained and the output value corresponding to x is formed as a weighted sum of the input values for these two integral y values and any intervening integral y values.

Abstract: The invention relates to a method and an apparatus for extracting packing rings from a stuffing-box, for example in a pump, a compressor or a valve.An object of the invention is to allow easy and quick extraction of the rings even when the access to the rings is not convenient.After opening the stuffing-box, a nozzle 39 of reduced dimension, carried by an arm 38 linked to a high pressure water supply, the pressure being of the order of 800 bars, is located above the first ring 32, approximately at the middle of its width; the arm is maintained by a fastening means 42 to the yoke of the valve. The water jet bores a hole in at least the first ring, which eliminates its internal mechanical stress and the water flowing through the hole is pushed back by the next ring, and lifts the first ring out of its housing.

Abstract: A roller-type ultrasonic inspection device for inspecting vehicle tires comprises a roller assembly 20 mounted on a non-rotatable hug 16. Two piezoelectric crystals 80,82 are mounted in the hub 16 such that their principal transmitting/receiving axes A and B converge generally radially outwardly of the hub. The angle between the axes A and B is selected such that when the roller assembly 20 is urged into rolling contact with the tread-bearing surface of a tire 90, the axes meet (allowing for refraction effects) in the body of the tire beneath the tread. This ensures that the device can detect defects in the body of the tire, and is relatively insensitive to the tread.

Abstract: A visually and electronically readable motor driven register has a plurality of dependently rotatable, coaxial, incrementally positionable, number wheels which each carry a movable electrode fixed in a predetermined position relative to the numbers on each wheel. Adjacent each movable electrode is inserted a fixed plate which carries a plurality of stationary electrodes, each corresponding to a number on the wheel and disposed circumferentially around a stationary main electrode which is capacitively coupled to the movable electrode. When a number on a wheel is visually readable, the movable electrode will be positioned so as to be capacitively coupled only to the stationary electrode corresponding to the readable number. A microprocessor provides pulses sequentially to the stationary electrodes of each wheel, and checks for a coincident processed output from the main electrode of the first wheel.

Abstract: A survey recorder for measuring electrical loads and providing a magnetic tape record of data with time reference signals in format capable of providing computer compatible information. The data recording circuit utilizes a light emitting diode with a phototransistor to determine each quantum measurement by the meter, and a trigger circuit driven by the phototransistor feeds a solid state divider circuit which is programmable to provide various I/O pulse ratio outputs to the data recording head. A power outage circuit detects outages which are greater than a predetermined duration and provides distinctive pulses to a time recording circuit to effect a recognizable format on the magnetic tape which identifies the power outage.