Abstract: Airborne Tacan equipment includes a receiver to receive Tacan signals and to provide an output signal having modulation components containing bearing information. The receiver includes a logarithmic amplifier to preserve the amplitude modulation of the modulation components and to enable operation on input signals having large amplitude variations. An arrangement is coupled to the receiver to at least partially compensate for the non-linearity of the logarithmic amplifier prior to extraction of the bearing information.

Abstract: A phase locked looped type frequency synthesizer utilizing a source of a reference signal comprising a voltage controlled oscillator and a phase detector which receives the reference signal and compares that to the output signal of the voltage control oscillator after suitable division by a programmable divider. The phase detector outputs a control voltage to the oscillator thereby regulating the output frequency from the oscillator wherein the programmable divider is programmed to divide or count by N, where N is capable of being a division number which is an integer or non-integer thereby allowing an increasing of the reference frequency and a decreasing of the settling time of the system without a need to increase the channel spacing.

Abstract: There is disclosed a threshold circuit for a long coded pulse having a given amplitude subdivided into a plurality of chips, each providing a code bit. A first circuit receives the coded pulse to compress the coded pulse into a shorter pulse of much greater amplitude than the given amplitude and to detect the compressed pulse. A second circuit also receives the coded pulse, detects the coded pulse and provides an amplitude threshold voltage. A third circuit coupled to the first and second circuits produces a finite output when the amplitude of the compressed pulse is greater than the amplitude of the threshold voltage and a zero output when the amplitude of the compressed pulse is less than the amplitude of the threshold voltage.

Abstract: Solid state apparatus for transmitting signals in an air communication, navigational or identification system wherein a signal generator produces pulses of a desired character and repetition rate. In a normal mode of operation, Gaussian-shape pulses are formed by subjecting a linear phase or Gaussian filter to impulse signals. A responsive amplifier produces pulse signals for driving an RF transmitter which broadcasts air communication, navigational or identification signals. The signal generator and amplifier receive operating voltages from a power supply having an output characteristic such that the amplitude of the signal generator and amplifier output signals are reduced relative to increased pulse repetition rate in order to prevent overdriving the transmitter and to maintain optimum system efficiency.

Abstract: An adapter is provided for insertion between a conventional DME airborne interrogator and antenna. The adpater converts conventional interrogations into phase-coded or amplitude coded signals which are received by new Microwave Landing System (MLS) transponders. Each transponder will process interrogations having the correct code and frequency and will respond with precision reply signals. The precision replies are then received by the airborne equipment, converted back to standard reply pulses and processed to provide distance measurement. Also provided is a new transponder for use at MLS sites.

Abstract: This relates to a channeling scheme for introducing a new service in the TACAN frequency band which can operate independently of the conventional TACAN system or in conjunction with it. Specifically, the new service is that of providing precision DME for a microwave landing system and for allowing existing TACAN airborne sets, when equipped with an adapter, to utilize new MLS ground beacons. In one channeling scheme, interrogations occur in frequency bands adjacent the standard TACAN interrogation band, and ground transmissions occur in frequency bands presently occupied by X mode reply signals. In a second scheme, which contemplates the use of standard airborne equipment provided with an adapter, interrogations occur within the conventional TACAN interrogation band, and replies occur in the bands now occupied by X mode reply signals.