Abstract: A distributed monitoring and protection system for a distributed power network. The system includes a plurality of high-speed measuring units (MUs), wherein each MU is coupled to a power line to measure values of electrical parameters of the power line. Electrical parameters, such as current, voltage, power and frequency are measured by the MUs. The MUs communicate with a control unit (CU) over a high-speed communications network. The CU includes a processor executing algorithms for evaluating the measured parameters to determine the status of the power network and the MUs. The processor also executes fault detection and isolation by comparing the measured values against predetermined threshold values. When a fault is detected by the CU, protective action, such as tripping of a circuit breaker, may be initiated by the CU directly or by transmitting the tripping command over the high speed data network to a local MU. The local MU may then trip the circuit breaker.

Abstract: A distributed monitoring and protection system for a distributed power network. The system includes a plurality of high-speed measuring units (MUs), wherein each MU is coupled to a power line to measure values of electrical parameters of the power line. Electrical parameters, such as current, voltage, power and frequency are measured by the MUs. The MUs communicate with a control unit (CU) over a high-speed communications network. The CU includes a processor executing algorithms for evaluating the measured parameters to determine the status of the power network and the MUs. The processor also executes fault detection and isolation by comparing the measured values against predetermined threshold values. When a fault is detected by the CU, protective action, such as tripping of a circuit breaker, may be initiated by the CU directly or by transmitting the tripping command over the high speed data network to a local MU. The local MU may then trip the circuit breaker.

Abstract: There is disclosed a digital enhancement circuit which responds to the complementary inductance provided by a planar coil sensor which inductance varies in a complementary manner according to the position of a movable member associated with the planar coil configuration. The complementary inductance is coupled to an oscillator whereby the period of the oscillator is varied in a first mode according to a first inductance value and in a second mode according to a second inductance value. These signals are then processed by means of digital processing circuitry to develop a signal indicative of the difference of the periods as divided by the sum of the periods. This signal is a ratiometric signal, and by employing digital counters, one can provide an output signal having a predetermined gain factor and having the above noted ratiometric characteristic which signal is indicative of the position of the movable member as further enhanced by the gain factor.

Abstract: There is disclosed a key which is particularly adapted for use in a musical keyboard. The key includes a top pivotable member which acts as a key surface and which is pivoted to move with respect to a reference plane. The key contains on a bottom surface a magnetic field effecting member. Located beneath the key on the reference plane is a rigid board containing a planar coil configuration. As the hinge member is moved towards the rigid board, the member affects the magnetic field of the planar coil configuration to vary the inductance as well as the magnetic coupling in other arrangements. A plurality of such keys are employed as the keys in a musical keyboard and are associated with frequency determining circuits such as oscillators to provide output frequencies necessary for the control of music.

Abstract: An electronic bathroom scale employs a low profile planar coil position sensor which responds to the positioning of a pivotable lever system. The levers are coupled to a platform which moves in the vertical direction as a weight is placed upon the top or supporting platform of the scale. The sensor provides variable amplitude or frequency proportional to the weight on the scale. The output signal is processed so that a direct reading of the weight is displayed by means of a digital display. The circuitry described serves to compensate for the nonlinearity of the transducer while further providing other compensation to eliminate environmental effects such as temperature and other factors from affecting the direct display of weight.