Abstract: The disclosure is applicable for use in a logging-while-drilling apparatus for obtaining subsurface measurements during drilling in a fluid-filled borehole. Acoustic carrier waves are generated downhole in the borehole fluid and are PSK modulated in accordance with digital data representative of the measurements. The PSK modulation is obtained by momentarily unidirectionally either decreasing or increasing the frequency of the acoustic carrier signal until either a desired phase lag (for a decrease in frequency) or phase lead (for an increase in frequency) is imparted to the acoustic carrier signal. An uphole receiving subsystem includes transducers for converting the modulated acoustic carrier waves to electronic signals and circuitry for demodulating the electronic signals to recover the measurement information taken downhole.

Abstract: The disclosure is applicable for use in a logging-while-drilling apparatus for obtaining subsurface measurements during drilling in a fluid-filled borehole. Acoustic carrier waves are generated downhole in the borehole fluid and are PSK modulated in accordance with digital data representative of downhole measurements. The PSK modulation is obtained by momentarily unidirectionally either decreasing or increasing the frequency of the acoustic carrier signal until either a desired phase lag (for a decrease in frequency) or phase lead (for an increase in frequency) is imparted to the acoustic carrier signal. An uphole receiving subsystem includes transducers for converting the modulated acoustic carrier waves to electronic signals and circuitry for demodulating the electronic signals to recover the measurement information taken downhole. In accordance with an important feature of the invention, a filter is provided for selectively filtering the electronic signals before the demodulation thereof.

Abstract: A radiosonde comprising a transmitter, a modulating oscillator, a control circuit for the oscillator and sensing elements to be switched into and out of said control circuit, characterized in that a solid state switching circuit is utilized for switching the sensing elements into and out of said control circuit to produce atmospheric information signals and with the sensing elements out of the control circuit there is produced a reference signal which reflects essentially the same impedance from the solid state switching circuit as is reflected in the atmospheric information signals thereby providing for evaluation of the information signals.

Abstract: A gas analyser of the infra-red radiation absorption type, particularly for measuring the amounts of CO.sub.2 and CO in vehicle exhaust gases, comprises a pair of infra-red radiation sources arranged to direct their radiation along a measurement path and a reference path respectively, the radiation entering each path being periodically interrupted by a rotating commutator. Two measurement chambers for receiving the gas to be analysed and respective detection chambers for CO.sub.2 and CO are alternately disposed along the measurement path, while two reference chambers and two more such detection chambers are alternately disposed along the reference path, corresponding detection chambers being connected to respective differential pressure sensors of the variable capacitance type. The analyser includes a calibration cell containing predetermined concentrations of CO.sub.2 and CO. The cell is selectively interposable in the measurement path, and is connected to a flexible-wall chamber.

Abstract: A variable filter having a plurality of different loopwidths is disclosed. The variable filter, which is typically employed in a phase locked loop, includes a plurality of capacitors which are switchably coupled into and out of operation in the filter in order to change loopwidths. Those of the capacitors which are not currently operational in the filter are precharged so as to prevent loss of lock in the phase locked loop when switching to another loopwidth.

Abstract: A line buffer circuit for coupling an interface to a data highway without requiring separate signal paths for sense and drive functions, comprises a unity-gain voltage amplifier coupling a line in the highway to the respective interface terminal for the sense function, and a current source connected to sink current from the highway line to ground for the drive function. The current source is controlled so that the current passing through it is proportional to the magnitude of the current passing from the amplifier through the interface terminal.

Abstract: Disclosed is a watthour meter box which allows simple disconnection of the meter and which includes a meter socket rotatably engaging the meter and a housing structure permitting the meter to be rotated from a first position where the meter is fully connected electrically to the meter socket to a second position where the meter is not fully connected electrically to the meter socket. In a preferred embodiment, the invention includes a stationary front panel having an oblong opening to admit the glass portion of the watthour meter and a movable plate behind the front wall having a similar oblong opening with a gasket reducing the opening to match substantially the perimeter of the glass wall of the meter. By releasing means securing the position of the movable plate, the meter rotates about a pivot member in the lower jaws of the socket and disengages its upper prongs from the upper jaws. Also disclosed are means securing the movable plate in the second disengaged position.

Abstract: A track and hold system for use with a test instrument such as a multimeter includes an input circuit, a buffer amplifier, a storage device such as a capacitor, an output amplifier, an output circuit, a detector for detecting a pulse on a signal passing from the input to the output, and a switch responsive to the detector for isolating the storage device from the input circuit but not the output circuit for a predetermined period. The system also includes a timer responsive to the detector to provide an isolation command to the switch for the predetermined period. Further, the system includes a delay circuit, responsive to the detector, for interposing a delay of variable duration prior to activating the timer.

Abstract: A position indicator is disclosed which includes the combination of a linear voltage differential transformer (LVDT) and accuracy assurance circuitry. The LVDT includes a movable core connected to a mechanism whose position is to be indicated. The accuracy assurance circuitry permits the disclosed indicator to operate substantially independent of fluctuations in input voltage or frequency. This substantial independence is achieved in the following manner. First, the voltage across the LVDT is rectified by a first precision rectifier. Simultaneously, the LVDT tap voltage is rectified by a second precision rectifier. Each precision rectifier output is filtered and then applied to an analog divider which "cancels out" the effects of input voltage or frequency fluctuation. The divider output is an analog signal which is a true ratio of tap voltage to voltage across the LVDT. This true ratio signal accurately represents the position of the mechanism connected to the movable core.

Abstract: A compact meter with a unitary bridge including magnet support legs to which a magnet is clamped by a magnetically permeable plate and a U-shaped magnet support. Locating surfaces on the bridge cooperate with locating surfaces on the magnet, on the plate, and on the magnet support to locate these elements with respect to the bridge and the rotor. The magnetically permeable plate extends through the coil, and the region below the magnet is substantially unobstructed so that magnets of different thicknesses can be substituted, while using the same bridge, rotor and coil assembly, and plate. In a preferred embodiment the magnetically permeable plate has offset ends which permit inverting the plate to accommodate magnets of two different thicknesses while alowing the use of the same magnet support. The rotor is of composite, solder-free and cement free construction, and includes a unique clamp together arrangement for securing the several parts of the rotor together in proper positional relationship.

Abstract: Apparatus for controlling an odometer and speedometer system of a vehicle, adjustable for vehicle parameter variations, such as tire size and axle ratio, including a transducer for generating a plurality of initial pulses in response to vehicle movement which pulses control both the vehicle odometer and speedometer. The initial pulses are multiplied by a multiplying factor to produce a train of pulses for each initial pulse. The multiplying factor is in binary form and is selected either according to the position of an array of switches or according to a number retained in a programmable downcounter. The train of pulses is divided by a fixed number to create a driving signal for the odometer and is converted by a frequency converter to drive the speedometer.

Abstract: A printed circuit mother board, for interconnecting the respective edge connectors of a plurality of other printed circuit boards having digital circuitry thereon, has a set of generally straight, approximately parallel tracks on each side. Each set of tracks comprises alternate signal tracks and ground tracks, and the ground tracks of each set are interconnected with each other to approximate to a ground plane. Additionally, the tracks on one side of the board are slightly laterally displaced with respect to the tracks on the other side, so that each signal track on either side is opposite a ground track on the other side. The possibility of interference between signals carried by the signal tracks is thus reduced, and the board has transmission line characteristics.

Abstract: A digital voltmeter for measuring an input voltage which can lie in any one of M successive ranges comprises an input scaling device which scales the input voltage to produce a voltage lying in a single predetermined range, and which also produces a range signal indicative of the range in which the input voltage lies. An analogue-to-digital conversion circuit then converts the scaled voltage to a corresponding digital signal which has up to N significant decade figures of resolution, where N<M. The voltmeter has a display unit with M decades, each of which represents a fixed order of magnitude of the input voltage, and control means responsive to the range signal to direct the digital signal to the group of N adjacent decades of the display means appropriate to the magnitude of the input voltage.

Abstract: A displacement transducer comprises a charge coupled device having a plurality of light sensitive stages arranged in a line. An obturating member connected to a member whose displacement is to be transduced is disposed between the charge coupled device and a light source. As the obturating member is moved, it varies the amount of light received by the respective stages of the charge coupled device, so that the charge distribution in the charge coupled device is representative of the position of the obturating member and therefore of the member whose displacement is to be transduced.

Abstract: A correction circuit for correcting the frequency of the output pulses produced by a gas flowmeter in dependence on the temperature of the gas comprises a control input for receiving a voltage representative of the difference between the temperature of the gas and a reference temperature. A voltage-controlled oscillator, operative during fixed short periods initiated by each flowmeter pulse, produces auxiliary pulses at a rate dependent on the voltage at the control input, and the auxiliary pulses are counted in a counter. Each time the counter counts a predetermined number of auxiliary pulses, it produces a signal which either blocks one flowmeter pulse or adds an additional pulse to the flowmeter pulses, in dependence on the polarity of the temperature difference.

Abstract: An electrical device such as a panel meter with a body including an abutment, is inserted through an opening in a panel with the abutment on one side of the panel, and is secured to the panel with a nut plate on the other side of the panel. The body of the meter has plural teeth, discontinuous around the periphery of the body and the teeth extend from opposite sides of the body. The nut plate has an opening with flexible sides to enable snapping the nut plate over the body and teeth to a position abutting the panel to clamp the meter to the panel. Portions of the opening in the nut plate are enlarged so that moving the nut plate to a position in which the body teeth are adjacent the enlarged portions of the opening releases the nut to permit immediate and rapid removal of the meter from the panel. There are several teeth at each side of the body to enable mounting and securing the meter in panels of substantially different thicknesses.

Abstract: An AC display excitation and synchronous display updating circuit for a digital electronic instrument in which the counter accumulating clock pulses representative of the magnitude of the quantity to be represented on the digital display is used as a frequency divider to obtain an AC display energizing signal whose frequency is reduced from the clock frequency to a suitable level for energizing the display. The contents of the continuously driven counter are synchronously transferred to the display register at the end of the conversion cycle by the use of a two-phase clock.

Abstract: Apparatus for measuring the phase difference between two electrical signals Asin (wt+.theta.), Bsin (wt+.phi.), given a reference signal Vsin wt generated by the apparatus, comprises a phase lock loop for generating a clock frequency f = 360F where F is the frequency of the reference signal. This clock frequency f is then used to tune a 360 stage CCD transversal filter which is used to filter successively the two first-mentioned signals, whose phase difference is then measured by a zero intercept system. The clock frequency f is used to give phase difference in degrees.The phase lock loop comprises a 90-stage CCD to which the reference signal is applied. The output of the CCD is applied to one input of a phase sensitive detector whose other input is connected to receive the reference signal, and the control signal produced by the phase sensitive detector controls a voltage controlled oscillator whose output is applied to the clock input of the CCD.

Abstract: The disclosed linearization system and process converts a high resolution non-linear analog input signal, representative of the thickness of an object, into a high resolution linear analog output signal suitable for use in driving a variety of output devices. The system requires only a small amount of memory for storing pre-calculated non-linear correction coefficients. Prior art linearization systems typically require large memory configurations and/or powerful computers to develop the output signal from the non-linear input. The known systems do not take advantage of the high resolution inherent in the input signal. The disclosed system "channels" the input signal to separate circuit paths so that it may be used directly to; (1) locate an appropriate correction coefficient; (2) develop a correction term after an appropriate correction coefficient is located; and (3) develop a linearized signal having the same high resolution inherent in the input signal.

Abstract: In a spectrum analyzer, the analogue signal to be analyzed is periodically sampled and digitized, and the digit samples are formed into R successive arrays each containing 2N successive samples and each overlapping the previous array by 50%. The forward Fourier transforms of each array are then successively formed, and an array of 2P complex points is formed from the result of each transform, where L-P/2 and L+P/2-1 are the points which represent the upper and lower limits of a Vernier band to be studied in detail and each array extends from points L-P to L+P-1 (i.e. each array is twice the width of the Vernier band, and the Vernier band is symmetrically disposed therein): additionally, each array for which L and R are odd is complemented. The arrays thus formed are then each multiplied by a window function (effectively equivalent to a band pass filter), and the result is subjected to the inverse Fourier transform to form respective further arrays of 2P points.