Abstract: A method of testing a product for the detection of the presence therein of a defect such as a void or an inclusion, comprises cutting the product and examining the resultant noise for the presence therein of an acoustic component representative of the presence of the inclusion. The method is applied to the processing of metal into slabs, bars, rods, wire strip etc., where the ends must be cropped to remove defective material, specifically to the continuous processing of strip metal where metal strips are joined continuously end-to-end, and where the ends of each strip as rolled may include undesired inclusions such as slag. A leading end piece is cropped by a shear, and the cropping of such pieces is continued until the testing method shows that the material at the place of the cut is free of the undesired inclusions.

Abstract: Method of monitoring equipment wherein a measured value signal in the form of an electrical a-c signal is fed to the measuring channel of an electric circuit and a mean value output signal is formed by the electronic circuit in accordance with the amplitude of the measured value signal, which includes setting an amplitude limit as a function of the mean value signal and the amplitudes of the measured value signal, automatically adapting the amplitude limit with a predetermined time constant to changes in the mean value signal, setting a limit of a number of occurrences when the amplitudes of the measured value signal exceed the amplitude limit, and activating an alarm if the occurrence limit is surpassed within a settable time period, and system for carrying out the method.

Abstract: A controlled carrier current measuring sensor/transducer signal amplifier system comprising a carrier oscillator for providing a carrier voltage oscillatory signal of known frequency and fixed voltage magnitude. A differential amplifier has the carrier voltage oscillatory signal supplied to one of its inputs. A reference impedance and a variable impedance sensor transducer are connected in a series circuit across the output of the differential amplifier and a first feedback signal is fed back to a second input of the differential amplifier with the first feedback signal comprising the sum of the voltage across the reference impedance and the variable impedance sensor transducer. A buffer amplifier has its input connected to the juncture of the reference impedance and the variable impedance sensor/transducer for deriving an output voltage representative of the instantaneous value of the voltage across the variable impedance sensor/transducer.

Abstract: A diaphragm formed in a substrate and having a piezoelectric surface includes a first surface acoustic wave (SAW) delay line disposed on said surface and connected in an oscillator circuit for a significant frequency sensitivity to surface strain of said diaphragm, and a second, similar oscillator with the SAW delay line thereof connected for a significant frequency sensitivity to surface strain of the diaphragm opposite in sense to that of the first oscillator, and a mixer for providing the difference in the frequencies of the two oscillators, whereby the overall sensitivity to strain is enhanced, while at the same time the sensitivity to temperature variations is reduced significantly through subtractive combination.

Abstract: The present invention is an apparatus for detecting the breaking of a glass plate. The invention uses a piezoelectric element, a signal separating circuit and a gate circuit. The piezoelectric element converts the vibrations of the glass plate into an electrical signal. The signal separation circuit separates the electrical signal into two signal signal components. The first signal component has a frequency range of less than 50 kHz. The second signal component has a frequency component higher than 100 kHz. The gate circuit produces an output signal only when both of the signal components have a signal level higher than their respective predetermined levels. By simultaneous detection of both of the first and second signal components, erroneous indication of the breaking of a glass plate can be prevented.

Abstract: A method and apparatus for electronically monitoring the condition of an object which normally emits stationary stochastic signals is disclosed wherein electronic signals representative of the emitted signals are generated in a plurality of at least two frequency bands and the kurtosis coefficient for these signals is determined over a period of time. Variations of the kurtosis coefficient are detected to provide an indication of the condition of the object.

Abstract: A detector for producing an output corresponding to the vibration of a cutting tool or a workpiece worked thereby, a signal processing circuit for obtaining the root mean square value of the output signal from the detector, and a comparator for comparing the output signal from the signal processing circuit with data produced at the time of normal cutting whereby when an abnormal vibration occurs due to the damage of the cutting tool the cutting operation is stopped by using a signal from the comparator.

Abstract: Electric currents induced by a magnetic field being moved in relation to a fixed coil, by a vertical displacement of the net cable/tennis net, enables a referee to detect the occurrence of a "let-ball.

Abstract: A device for measuring parameters of impact pulses comprises an acceleration pickup which converts mechanical vibrations of an object being studied into electrical signals, said electrical signals being supplied through an amplification unit to a means for measuring the impact speed variation.