Abstract: A method of removing undesired signals in an aviation guidance system may include receiving at least one first desired signal having a first frequency of amplitude modulation, receiving at least one second desired signal having a second frequency of amplitude modulation, and receiving at least one undesired signal having any frequency including a frequency that is substantially the same as or a subharmonic of at least one of the first and second desired signals. The first and second frequencies of amplitude modulation are phase synchronous, and the undesired signals are non-synchronous with at least one of the first and second desired signals. The method may also include identifying the undesired signals and removing the undesired signals.

Abstract: A method and apparatus are provided for initializing ionization of a gas discharge display. The gas discharge display includes a keep-alive area electronically coupled to circuitry including one or more light emitting diode (LED). The keep-alive chamber is also optically coupled to the LED. The circuitry measures current through the keep-alive area and the method includes the step of activating the LED in response to the current through the keep-alive area falling below a predetermined threshold current.

Abstract: Signal processing systems for radar installations are provided for simultaneous processing of one or more IF signals of dynamically varying frequency and bandwidth with a single analog signal path. The signal processing system includes, but is not limited to, a converter configured to digitize a return signal resulting in a digitized broadband signal, and a signal processor coupled to the converter. The signal processor includes a digital filter having a center frequency and a bandwidth, and the digital filter is configured to select a signal from the digitized broadband signal. The selected signal has a center frequency. The signal processor is configured to match the center frequency of the digital filter with the center frequency of the selected signal, and adjust the bandwidth of the digital filter based on the selected signal.