Abstract: A method and system is disclosed for determining the location of a member of a class of individual transmitter-receiver units distributed throughout a defined facility. A central station establishes a two-way communication channel with one or more relay stations and sends a coded message identifying a particular individual unit over the communication channel. The relay stations respond to the message by sending out wake-up signals and radiant energy inquiry signals. The individual unit identified in the inquiry signal responds with a radiant energy acknowledgment signal. Embodiments of the invention disclose the use of infrared energy or ultrasonic energy for the radiant energy. Ultrasonic signals are sent on a plurality of frequencies. The relay stations send identification signals to the central station which identify the sending relay station and indicate whether an acknowledgment signal was received.

Abstract: A synchro power amplifier and control circuit for an inductive load has a plurality of synchro leg amplifiers connected to the load. Each amplifier has an interstage transformer for deriving samples of current drawn by the load. A multiplicity of capacitors are respectively connectable in parallel with the (load) upstream of the amplifiers by switches in a circuit 10 responsive to the voltage/current phase angle of the power driving the load, to compensate for the inductance of the load.

Abstract: In a switching dc-to-dc converter an output current substantially free of pulsations is provided by summing a flyback current and transformed current response to the current used to build up the electromagnetic field that stores the energy for flyback.

Abstract: In a switching dc-to-dc converter an output current substantially free of pulsations is provided by summing a flyback current and transformed current response to the current used to build up the electromagnetic field that stores the energy for flyback.

Abstract: A low cost airborne weather radar system suitable for mounting in the wing of a single engine aircraft. The radar antenna is a truncated parabolic dish. The receiver/transmitter, relative to parameters used in a conventional receiver/transmitter operates at relatively small peak transmitter power with a relatively long transmitter pulsewidth which, in turn, is matched to the receiver bandwidth. The relatively small peak power allows for acceptable range performance due to the relatively larger pulse width. Further, the receiver/transmitter assembly is significantly reduced in size so as to facilitate location in an aircraft wing and be thereby directly connected to the antenna to eliminate range reducing intercabling losses.