Abstract: Various circuits and methods are disclosed for communications over AC power lines. In one example embodiment, a power line communication circuit includes an analog front end having a data-coupling circuit configured to communicatively couple communication signals to and from a set of AC power lines in the power line communication system. The analog front end also includes a noise reduction circuit that is coupled to the data-coupling circuit. The noise reduction circuit is configured to mitigate noise within a communication frequency band of the communication signals by filtering, from the communication signals, at least one frequency that is located outside of the communication frequency band and that has harmonics located within the communication frequency band and to demodulate data from the communication frequency band of the filtered communication signals.

Abstract: Various circuits and methods are disclosed for communications over AC power lines. In one example embodiment, a power line communication circuit includes an analog front end having a data-coupling circuit configured to communicatively couple communication signals to and from a set of AC power lines in the power line communication system. The analog front end also includes a noise reduction circuit that is coupled to the data-coupling circuit. The noise reduction circuit is configured to mitigate noise within a communication frequency band of the communication signals by filtering, from the communication signals, at least one frequency that is located outside of the communication frequency band and that has harmonics located within the communication frequency band and to demodulate data from the communication frequency band of the filtered communication signals.

Abstract: Various circuits and methods are disclosed for communications over AC power lines. In one example embodiment, a power line communication circuit includes an analog front end having a data-coupling circuit configured to communicatively couple communication signals to and from a set of AC power lines in the power line communication system. The analog front end also includes a noise reduction circuit that is coupled to the data-coupling circuit. The noise reduction circuit is configured to mitigate noise within a communication frequency band of the communication signals by filtering, from the communication signals, at least one frequency that is located outside of the communication frequency band and that has harmonics located within the communication frequency band. A receiver circuit is coupled to the noise reduction circuit and is configured to demodulate data from the communication frequency band of the filtered communication signals.

Abstract: In one embodiment, a transmitter circuit is provided for data transmission from endpoint devices to collector devices over power distribution lines. The transmitter includes an amplifier circuit configured to receive and convert a first data signal to a pulse density modulation (PDM) encoded signal using high frequency pulses that introduce high frequency components. A low-pass filter of the transmitter is configured to filter the high frequency components of the PDM encoded signal to produce a second data signal, which is an amplification of the first data signal. A coupling circuit of the transmitter is configured to communicatively couple the second data signal from the low-pass filter to the power distribution lines. The coupling circuit filters the frequency of the AC and prevents high voltage of the power distribution lines from damaging the transmitter.

Abstract: In one embodiment, a transmitter circuit is provided for transmission of data over power distribution lines using any one of a plurality of carrier frequencies. A data signal generation circuit is configured to encode data bits using a selected carrier frequency. A signal strength module adjusts the signal strength of the data signal according to a signal strength setting, to produce an amplified data signal. A coupling circuit communicates, using a coupling capacitor, the amplified data signal. A current sensing circuit senses current provided to the power distribution lines as a function of degradation of the coupling capacitor. A signal level control circuit adjusts a signal strength setting of the signal strength module for the selected one of the plurality of carrier frequencies as a function of the sensed current and the selected one of the plurality of carrier frequencies.

Abstract: In one embodiment, a transmitter circuit is provided for data transmission from endpoint devices to collector devices over power distribution lines. The transmitter includes an amplifier circuit configured to receive and convert a first data signal to a pulse density modulation (PDM) encoded signal using high frequency pulses that introduce high frequency components. A low-pass filter of the transmitter is configured to filter the high frequency components of the PDM encoded signal to produce a second data signal, which is an amplification of the first data signal. A coupling circuit of the transmitter is configured to communicatively couple the second data signal from the low-pass filter to the power distribution lines. The coupling circuit filters the frequency of the AC and prevents high voltage of the power distribution lines from damaging the transmitter.

Abstract: A method for assembling a gas turbine engine compressor having a plurality of stages and a plurality of blades coupled to each respective stage includes depositing a silicone oxime sealant onto at least a portion of a compressor blade, and coupling the compressor blade to a compressor disk such that the silicone oxime sealant is between the compressor blade and the compressor disk.

Abstract: A method enables a variable vane assembly for a gas turbine engine including a casing and an inner shroud to be assembled. The method comprises providing at least one variable vane including a radially inner spindle that has a substantially circular cross-sectional shape, and coupling the variable vane radially between the casing and the inner shroud such that the radially inner spindle is rotatably coupled within an opening extending through the inner shroud, wherein the opening has a non-circular cross-sectional profile.