Abstract: A microprocessor-controlled airfield series lighting circuit communications system and method allows bi-directional communication between the controlling microprocessor and the airfield lamps. The bi-directional communications signals are formed by using a modulated radio-frequency signal that is transmitted through a circuit containing many transformers having their primary windings connected in series. Respective secondary windings of the transformers are connected to various devices, such as lamps or sensors. A high frequency signal is imposed on the series-connected primary windings to control the lamps. The frequency of this signal is selected to be able to be detected on the secondary side of the transformer. A remote controller is connected to the secondary of each transformer to receive the control signal and selectively switch power obtained from the transformer secondary to the respective connected device.

Abstract: Calibration apparatus for an antenna/receiver system having, in combination, means for receiving one or more electromagnetic data encoded signals from a transmitter and producing in response to each data signal two signals having a phase relationship, the receiving means comprising an antenna; signal processing means for using the phase relationship to determine information related to the data signals; and means for coupling a calibration signal into the antenna to produce two calibration signals having a known phase relationship; the signal processing means using the known phase relationship to compensate for phase errors when processing the data signals.

Abstract: Methods and apparatus for detecting and decoding transponder reply signals of the type having a plurality of associated time discrete pulses including two bracket pulses and a number of related data pulses that may have been transmitted at discrete data time intervals between the bracket pulses such that the signal content detected during the data time intervals corresponds to the reply signal data code, comprising receiver means for receiving the reply signals and producing in-phase (I), quadrature (Q) phase and video (V) signals for each received pulse; means for detecting received pulses and storing the I/Q/V signals in a first memory; means for storing in a second memory pointer values that correspond to the temporal location of pulse I/Q/V signals in the first memory; means for identifying, based on time of arrival (TOA) values, pairs of potential bracket pulses wherein each pair marks the beginning and end of a reply code; and processor means for 1) determining an angle of arrival (AOA) value for each d