Abstract: A solid-state barometric altimeter-encoder. The atmospheric pressure is cared to a reference vacuum on a hybrid IC pressure transducer which generates a proportional signal. This analog signal is then converted into digital data, corrected for atmospheric to altitude non-linearity by use of a ROM look-up table, displayed as a digital readout and also converted to Grey code format for transponder MC (altitude) transmission.

Abstract: A low profile camouflaged antenna for military vehicles and the like. The tenna comprises an elongated, typically rectangular, sheet of metal curved to conform to the curvature of the vehicle. Insulated spacers, for example of plastic or fiberglass, maintain a fixed spacing between the metal plate and the vehicle, thus forming two elongated slots which, when suitably energized, act as a dual-slot antenna.

Abstract: An auxiliary channel, for example, an engineering orderwire, is derived on n existing time-division multiplex carrier system by modulating the pulse repetition rate of the digital bitstream. The modulating signal itself may be an analog or a digital signal. The modulator and demodulator both include a first-in, first-out shift register acting as a buffer, and the desired modulation is effected by varying the rate at which the digital information is fed out of the FIFO buffer at the transmitting end of the carrier system.

Abstract: A VHF/UHF communications blade type antenna additionally having microwave nding system (MLS) antenna elements mounted thereon and having the microwave feed components integral therewith to provide a composite structure adapted to function both as a communications and as a navigation antenna. The antenna is particularly adapted for use with aircraft which is to be retrofitted to include MLS capability.

Abstract: A device for accurately measuring the quantative value of the real part of complex impedance without the measurement affecting or being affected by the reactive component of that impedance. The device is useful for impedance matching, and especially for tuning antennaes and the like such that the real part of the impedance can be appropriately matched with the source or receiver during tuning. The device operates by comparing the power delivered to the load with the power dissipated in a resistance R when a current proportional to the main line current passes through it. When both power readings are the same, which may be determined by a null indicator, the real part of the load impedance equals the resistance R.

Abstract: A system including a linear CCD sensor array included in a gated optical ar which is particularly adapted to permit pattern recognition of wire or wire-like obstacles during low level flight of the radar platform, e.g. helicopters or the like. The system provides a display and/or automatic warning to the pilot of the location of impending danger so that evasive action may be taken with as little human operator function as possible being required to perform the detection and recognition phase.

Abstract: A microstrip antenna design according to which the resonant frequency can substantially reduced for a given size radiator, or to which the size of the radiator can be reduced for a given resonant frequency. As will be seen, a microstrip antenna loading is accomplished through the removal of a central portion of the etched metal radiator, and the amount of loading is a function of the size of the central portion removed.

Abstract: An adaptive coder and decoder for reducing the bit rate required to trans digitally encoded speech signals. The invention relies on the fact that the speech pattern of the average talker contains significant numbers of inter-syllable and inter-word pauses. The coder includes circuitry that monitors the idle pattern code generated by the coder's analog-to-digital converter and a code word generator that generates one or more special code words that are substituted for idle pattern code sequences of predetermined length. The speech signal and special code words are then fed into an elastic buffer and transmitted to the distant receiver at a lower bit rate than was employed for the encoding process.

Abstract: A plurality of signals to be separated in time as well as in frequency are imultaneously applied to the input of a power amplifier whose output is applied to the input of a fast-tuned filter. The filter is capable of being almost-instantaneously tuned to any of the frequencies of the input signals to control the output at any given time or combinations of times. The filter is in the form of a coaxial section with an input to the inner conductor of the coaxial section and the output taken from a strip line, parallel to the inner coaxial conductor, coupled to a coaxial output cable at the top of the coaxial filter. The tuning is by a plurality of inductive spokes positioned at various locations within the filter, and connected between the inner and outer coaxial conductors by switching diodes, that are externally controlled, to provide almost instantaneous control of the resonant frequency of the filter.