Abstract: A transducer is utilized to convert the eccentricity of a turbine shaft into a sinusoidal electrical voltage signal having a given frequency, amplitude and a DC bias. This electrical signal is provided to a circuit which periodically measures the maximum and minimum peaks of the sinusoidal signal. The frequency at which the latter measurements occur is related to the frequency of the sinusoidal input signal. The maximum and minimum levels of magnitude are stored periodically as DC levels and subtracted from each other to determine the absolute value of eccentricity. In addition the stored minimum value is compared with the sinusoidal signal to reduce the DC bias of the sinusoidal signal to a point where the negative peaks thereof are at zero.

Abstract: A decoder for converting a frequency coded digital input signal into a binary output signal. The decoder includes circuitry which detects when the input signal consists of the proper tones. When these tones are present, the decoder circuitry converts the tone signals into constant amplitude squarewave signals. The squarewave signals are then attenuated and integrated, and these two signals are offset and applied to a comparator. The resulting signal from the comparator is in the form of a pulse signal having rectangular pulses of constant amplitude and width, with the repetition rate of the pulses being equal to the corresponding tone frequency. The rectangular pulse signal is filtered and converted into a binary signal having binary levels which correspond to the average value of the filtered pulse signal with respect to an adjustable reference value.

Abstract: An arrangement of components for a distribution line communication system. Two or more independent secondary distribution lines are connected, through distribution transformers, to a primary distribution line. Carrier communication signals are transferred between the primary distribution line and one of the secondary distribution lines by a repeater located near one of the transformers. The carrier communication signals are propagated directly along this secondary distribution line and through associated service lines to communications terminals located near the electrical loads. Coupling apparatus is connected between the two independent secondary distribution lines to provide a path for the communication signals between the repeater and the communications terminals associated with the other secondary distribution line. The coupling apparatus provides a low-impedance path for the communication signals and a high-impedance path for signals at conventional electrical power frequencies.

Abstract: Apparatus for connecting separate transmitters of a carrier communication system to the same location on a power distribution line. A low-power transmitter is connected to the primary winding of an interconnecting transformer. The secondary winding of the interconnecting transformer is connected between a high-power transmitter and, through the primary winding of a coupling transformer, to ground potential. The secondary winding of the coupling transformer is coupled to the power distribution line. A voltage limiting device is connected across the secondary winding of the interconnecting transformer. The output of the high-power transmitter is directed across the voltage limiting device to the coupling transformer where it is applied to the distribution line.