Abstract: Digital apparatus and a method are disclosed for determining the phase angle of a tone signal of known frequency by correlating a clipped version of the tone signal with a reference signal having a repetition rate equal to the tone frequency. Correlation is accomplished by multiplying the clipped tone signal with each of quadrature components of the reference signal and sampling the product signals to provide binary sample trains which are supplied to a pair of shift register accumulators which effectively frame a moving phase measurement window. Reversible counters and associated logic determine the magnitudes and signs of differences in numbers of samples of noncorresponding binary values in each of the accumulators, and provide counts representative of in-phase and quadrature components of the product of the tone signal and the reference signal. The counts are utilized in a digital processor to compute the phase angle of the tone signal relative to the reference signal.

Abstract: A method for detecting impending failure of suspension during an aqueous suspension polymerization has been developed by continuous monitoring of the electrical conductivity of the suspension system. A sudden drop in conductance warns of failure of suspension in time to save the suspension by the addition of suspension stabilizers. A special conductivity cell has been developed to allow measurement of conductance during the course of the polymerization reaction.

Abstract: An improved technique is disclosed for forming two- or three-dimensional images of a macroscopic sample by means of gyromagnetic resonance. A train of free induction decay transient resonance signals are induced and detected from a sample in a region to be imaged. A sequence of pulsed magnetic field gradients are applied during the series of free induction decay signals to derive sets of gyromagnetic resonance data as a function of the changing magnetic field gradients. Two- or three-dimensional images are reconstructed from the sets of resonance data by two- or three-dimensional Fourier transformation.

Abstract: Phases are measured with a resolution of one degree, and frequencies are measured with a resolution of 0.01 Hz by the same circuitry. An internal voltage-controlled oscillator (VCO) is forced to operate at 360 times the frequency of the incoming test signal by use of a phase-locked loop and a 360 divider. Clock pulses from the VCO are counted throughout an interval of noncoincidence of the original test signal and any phase-shifted version of that test signal, and the count is digitally displayed directly as phase shift in degrees. Clock pulses from the VCO are counted throughout an interval of (1/3.6) second and the resulting count is digitally displayed with the last two digits marked off by a decimal point, as the frequency.

Abstract: Two frequencies to be compared are applied to two inputs of a flip-flop. output of the flip-flop is fed to a low pass filter and the output of the filter is a saw tooth voltage proportional to the phase difference between the two frequencies. Differentiation of the saw tooth voltage yields a voltage proportional to the difference between the two frequencies. A threshold circuit is provided for sensing the output voltage of the filter to control a flip-flop which in turn reverses the phase of one of the frequency signals and disconnects the output of the differentiator from a capacitive storage circuit.

Abstract: A control system for a water rinse tank or the like which continuously monitors the rinse water quality by means of electrical conductivity and adds clean water when the water-contamination conductivity of the rinse water builds up through use to a predetermined value. A conductivity cell which is transparent and may be disassembled, and adjustable for operation over a wide range of conductivity settings. A power circuit with triac for switching power to a valve solenoid. A silicon controlled rectifier (SCR) and its associated circuitry located at the conductivity cell for controlling the triac, with the SCR operation directly controlled by the conductivity cell. A zener diode-transistor voltage regulating circuit for consistently maintaining substantially the same spiked waveform across the conductivity cell both for water off and water on conditions.

Abstract: A method of gyromagnetic resonance spectroscopy is disclosed which simplifies the resultant spectra by eliminating spin-spin coupling effects. The method is particularly useful for eliminating homonuclear spin-spin coupling effects. In the method, spin echo resonance of the resonators is obtained and the time elapsing between tipping of the resonators and detection of the resultant echo t.sub.1 is changed from one measurement to the next. The resultant echos are measured at equal intervals of time t.sub.2. Echo resonance data is Fourier transformed from the time domain into the frequency domain to obtain spectral data in the frequency domain as a function of t.sub.1. A second Fourier transform of the resonance data is then effected to transform the spectral data into data which is a function of both .omega..sub.1 and .omega..sub.2 where .omega..sub.1 and .omega..sub.2 are each related to 1/t.sub.1 and 1/t.sub.2, respectively. The spectral data in the .omega..sub.1 -.omega..sub.2 plane is then projected at 45.

Abstract: The position of a control rod located within a nuclear reactor is sensed by a position indicating system utilizing a series of self-exciting reed switch oscillator assemblies mounted along the path of control rod travel. Each reed switch oscillator assembly is preset to provide a constant level output signal when no external flux field is present and to provide an oscillating output signal whenever an external flux field is brought into the vicinity of the reed switch oscillator assembly. The control rod has a magnet mounted thereto which establishes an external flux field and causes the reed switch oscillator assembly proximate to the magnet to provide an oscillating output signal indicative of the position of the control rod.

Abstract: An apparatus and process for measuring the percent concentration of an electrolyte in solution is disclosed. The apparatus includes a crystal oscillator generating a square wave and a wave shaper to transform the wave into a monochromatic sine wave which passes through a two stage temperature compensated first buffer amplifier. The sine wave passes between electrodes which project into the solution under investigation and generates an output. A second buffer amplifier operates on the A.C. component of the output from the solution and is operatively connected to a half wave rectifier. The output of the half wave rectifier is proportional to the percent caustic. A temperature control device is utilized to hold the solution at a constant temperature.An alternate embodiment utilizes two identical circuits with two different solutions. One circuit is used with a solution having a known concentration and one with an unknown concentration. The outputs are compared in a differential amplifier.

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: RF excitation for a spectrometer is obtained by pulse width modulating an RF carrier to produce the desired broadband RF exciting spectrum. The RF excitation includes a train of composite RF pulses, each composite pulse having a primary pulse portion of a first RF phase and a second pulse portion of a second RF phase opposite that of the first. In this manner, the finite rise and fall times of the primary pulse portion are compensated for by the corresponding rise and fall times of the secondary pulse portion. The primary pulse portion is lengthened by an amount equal to the secondary pulse portion so that the secondary pulse portion cancels the added primary pulse portion. In a spectrometer the compensating second pulse component removes certain undesired side bands of the RF excitation caused by the finite rise and fall times of the applied RF pulses.

Abstract: A pair of field effect transistors are series connected with one acting as a current source to bias the second which acts as a source follower. A photodiode, connected between the source follower gate and source, operates in response to light to change the current in the source follower. The photodiode is biased by the collector of a bipolar transistor that is connected as a negative feedback amplifier operating around the source follower stage. This configuration maintains close to zero bias on the photodiode, particularly at low light levels, and ensures that the collector current in the bipolar transistor equals the photocurrent. An output bipolar transistor with an uncommitted collector matches the feedback transistor and has its emitter and base directly connected thereto. Thus the output current will track the photocurrent, which is a linear function of light input over a very large range of levels. The circuit is linearly operative to extremely low light levels.

Abstract: A magneto-optic cell comprising a composition responsive to magnetic fields. The composition comprises a ferrofluid and metal flakes which align with the ferrofluid in response to magnetic lines of force and along the magnetic lines of force. Detection of the presence of a magnetic field is thereby provided.

Abstract: The relative amounts of liquid phase versus vapor phase of a mixed phase conductive fluid, such as boiling water, is determined by conductivity measurement taken in several distributed directions overlapping within the cross section of a flow path by providing a rotating field vector therein with an alternating voltage on the order of 1-30 kilohertz, with conductivity measurement produced by the rotated field being divided by a liquid conductivity measurement to determine liquid fraction (and by subtraction from unity, vapor fraction), the rotating electrical field being produced by application of a multi-phase alternating current to groups of electrodes with poled pairs distributed in alternation around the periphery of the cross section to be measured, the electrode structure and intervening insulators defining a flow measuring cross section with allowance for rigors of flow conditions and fluid environment to provide reliable, long-lived effective measurement.

Abstract: A resonance thermometer utilizing nuclear quadrupole resonance, nuclear magnetic resonance or like resonance-absorption phenomenon. The thermometer includes an oscillator for oscillatively detecting a resonance in a resonant material, a means for modulating the oscillation frequency of the oscillator at a low frequency, a first detecting means with a short time constant for detecting a component from the modulated output of the oscillator, and a second detecting means with a long time constant for detecting a component from the modulated output of the oscillator. The oscillator frequency is swept in linear ramp fashion at high speed until an output from the first detecting means occurs, at which point the frequency sweep is stopped. The precise resonance-absorption frequency of the resonant material then is found by using the output of the second detecting means, and the temperature is derived from the precise resonance-absorption frequency.

Abstract: It has been determined that unique discharge signature waveform shapes are associated with the corona discharges in the components of the power separation filters of repeaters and equalizers. These signature waveform shapes, present across the repeater or equalizer terminals, can be measured and identified by artificially contaminating and inducing corona discharges in the high voltage components. A discharge signal subsequently generated in response to a corona discharge across a high voltage component of a repeater or equalizer of a similar type will have the same shape as one of the signature waveforms. Thus, a corona discharge from a repeater or equalizer under test can be located by comparing its discharge signal with the catalog of signature waveforms.

Abstract: In a directional fluorescent lamp having a reflector layer between the phosphor and the glass envelope wall, there is a dark, nonreflecting, light-absorbing layer between the reflector layer and the glass to prevent light escaping from the back of the lamp.

Abstract: An armature operation-release testing apparatus for an electromagnetic relay of the type in which an armature is adapted to move toward and away from a core in a direction different from the direction of movement of a movable contact. The test for the operating characteristic of the electromagnetic relay is carried out by supplying an operating current to the electromagnetic coil of the relay to attract the armature to the core, positioning an externally controlled sensor to a test position slightly displaced toward the armature beyond the armature attracting surface of the core, and detecting electrical engagement between the sensor and the armature. The test for the releasing characteristic of the relay is then carried out by supplying a releasing current to the coil in lieu of the operating current, positioning the sensor at the test position again, and detecting electrical engagement between the sensor and the armature.

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.

Abstract: Shaft position sensing apparatus includes a group of generally parallel vanes extending generally longitudinally of the shaft axis, means for mounting the vanes in that relationship and attaching them to the shaft for rotation with the shaft, a light source providing a beam of light directed transversely of the shaft axis against the vanes, and a light sensor aligned with the light beam and positioned on the opposite side of the shaft axis from the light source for receiving varying amounts of light dependent upon the angular position of the shaft.