Abstract: An apparatus and method is disclosed of providing higher quality speech transmission and reproduction. The present invention consists of a standard 2400 BPS transmitter with the addition of an additional 2400 BPS through a residual signal combined with the standard 2400 BPS signal. The addition of the residual signal gives more information about the speech signal being transmitted and allows more accurate reconstruction of the speech based on the received digital signal. The residual signal is adjusted to phase-align all frequency components to zero, then quantizing only the positive half of the residual signal now symmetric about zero time.

Abstract: An apparatus for performing a soft decision function prior to convolutional decoding in a data communication system using differential quadrature-PSK or other transmission schemes is disclosed. A memory element coupled between a demodulator and the convolutional decoder in a receiver portion of the communications system performs the soft decision function. The memory element contains data organized using probability of occurrence and Log-Likelihood parameters for each potential combination of current and past received signal modulation quantized at a predetermined level.

Abstract: A circuit which finds a synchronization pattern and provides synchronized data from incoming time division multiplexed data is disclosed. The incoming data includes an incoming clock signal used in saving the incoming data in a FIFO memory. A local clock, which is isolated from the incoming clock but exhibits substantially the same rate as the incoming clock, retrieves output data from the FIFO memory. A series of bits from the output data which includes bits having relative bit positions that correspond to the bit positions of the synchronization pattern are examined for the occurrence of the synchronization pattern. If the synchronization pattern is not found, a dummy bit is added to the incoming data stream. The added dummy bit causes the quantity of data stored in the FIFO memory to increase the delays the output data by one bit relative to the output data prior to the addition of the dummy bit. The above described process repeats until synchronization is achieved.

Abstract: A radar transceiver and communications transmitter mounted on a target for communicating video signals from the radar to a remote receiver which has associated therewith an FFT detector for detecting scoring encounters, and a computer or microprocessor which first analyzes the video signals to provide signals indicative of the Doppler frequency shift at a plurality of different times through the use of autoregressive spectral estimation and then computes a model projectile flight pattern, including miss distance and closing velocity, which flight pattern fits the computed Doppler frequency shifts at the plurality of different times.

Abstract: A radio receiver circuit which suppresses an interfering signal exhibiting an amplitude significantly greater than that of a desired signal and a frequency nearly the same as that of the desired signal is disclosed. A received signal is applied to a gain controlled amplifier and a limiter. The limiter provides a limited signal which reduces amplitude and power of the desired signal relative to the interfering signal. The gain controlled amplifier provides a constant amplitude signal at an amplitude where the interfering signal portion of the constant amplitude signal equals an amplitude of the interfering signal portion of the limited signal. The constant amplitude and limited signals combine through a subtraction operation resulting in a significant attenuation of the interfering signal while causing only a small attenuation of the desired signal. Switching and decision circuitry are provided to selectively utilize the interference suppression.

Abstract: A pulsed Doppler radar mounted adjacent to the tip of a helicopter rotor blade for sensing obstacles in the helicopter path. The rotor tip velocity shifts the frequency of radar echos so that, through pulsed Doppler radar techniques, the echos from obstacles can be separated from clutter.

Abstract: An electronic encoder for use in setting fuzes in munitions and the like. The electronic encoder comprising: a switch which activates the electronic encoder by coupling in the power supply and which is used to set the electronic encoder; a display for displaying the setting of the electronic encoder; a display driver for driving the display; a selector operated by the switch for selecting a digit of the display to be set; and a setting device operated by the switch for setting the portion of the display. This setting, when completed, is transmitted to the fuse of the munition or the like.

Abstract: A resistive element is formed on a printed circuit board using only printed circuit board fabrication techniques. Two printed circuit board strata are laminated together into a multi-layer printed circuit board. A desired trace pattern is etched into a first layer of a first stratum that has first and second conductive metallic layers clad to opposing sides of a first dielectric substrate. A bi-metallic clad substrate having a resistive layer clad to a first side of a second dielectric substrate, a third conductive layer clad to the resistive layer, and a fourth conductive layer clad to a second side of the second dielectric substrate represents the second stratum. The third conductive layer is etched to leave only pads. The resistive layer is etched to form resistive elements of desired resistivity between the pads. When the two strata are laminated together, the pads couple to the trace pattern at desired locations.

Abstract: A split-phase integrate and dump matched filter utilizes both the positive and negative inputs of a single comparator and adds an exclusive-OR logic element after the matched filter to correct the data polarity since the negative-input path of the data output is inverted.

Abstract: A radar system includes a variable delay circuit coupled between the transmitter and the receiver switch. A feedback loop including a comparator and an integrator is coupled between the receiver envelope detector and a control terminal for the variable delay circuit. The feedback loop controls the amount of delay of the receiver switch to maximize sensitivity to close range targets.

Abstract: A microminiature oscillator that uses the movement of a mechanical structure placed on an etched silicon chip to control the frequency of a pulse used as a time base in electronic applications.

Abstract: A directional filter wherein dielectric resonators tuned to the operating frequency couple electric energy from port one to port four while electrical energy at other frequencies passes through the filter to port two.

Abstract: A method for repairing fine leaks in the envelope of hermetically sealed packages is accomplished by using a liquid silicate and solvent mixture which is liquid well below the melting point of glass and which leaves a silicate patch after the solvent is removed.

Abstract: An active optical sensing device and method which uses a transmitter to transmit directional electromagnetic radiation and a plurality of detecting devices for receiving radiation reflected off of a target and for providing output signals in response thereto. The signals are sent to a logic circuit for processing in time and amplitude to differentiate between a target and an aerosol.

Abstract: A monopulse tracking system utilizing at least two channels, each of which has a different spreading/despreading pseudo-random noise function associated therewith. In conjunction with a monopulse antenna, one of the channels is utilized to develop a sum signal and the other channel is utilized to develop a difference signal, which sum and difference signals are utilized in a phase detector to generate an error signal. Because different channels are utilized to develop the sum and difference signals, externally generated noise is uncorrelated in the phase detector and, therefore, biases caused by the noise are eliminated.

Abstract: A dual adjacent directional filter is disclosed for the splitting and combining of signals. This device is composed of a six port filter wherein if the appropriate signal is entered into the center port two signals having the same frequency as the input signal and equally divided amplitudes will output to the corresponding two output ports. This device is comprised of two transmission lines being equally divided by an impedance matching transmission line. Between the impedance matching transmission line and the regular transmission lines is located a filtering device of either a loop type transmission line; resonator; or transmission stubs.

Abstract: A demodulator for shaped BPSK signals that utilizes switches which have switching control means designed to eliminate unwanted Q channel signal power and unwanted carrier phase error signal power by opening the switches during the phase transition portions of the shaped BPSK signals. The switching control means close the switches during non-transitional portions of the shaped BPSK signals.

Abstract: This is a method for an adaptive delay time after impact of a projectile by determining the spin rate of the projectile using spin switches to set a time delay which may then be updated using a time of flight counter. This method may be used on artillery shells of varying calibers and each caliber of which has varying velocities.

Abstract: A square diaphragm formed of monocrystalline silicon and integrally attached to a silicon frame surrounding the diaphragm at its four edges. A serpentine resistor is diffused into the surface of the diaphragm adjacent each of the edges and the resistors are connected in a Wheatstone bridge configuration. The frame of the diaphragm is anodically bonded to a pyrex base member so that all four edges of the diaphragm are fixed relative to the base member and each other. The volume between the base member and the diaphragm is vented to prevent any differential pressure from occurring on the diaphragm.

Abstract: An apparatus and method is described for linearizing a non-linear device. This circuit consists of a detecting device for detecting a signal when received. A feedback device for providing a feedback signal. An operational amplifier and a bias means. These devices are coupled to provide an output that is linearly dependent upon the input to the circuit and not upon the amplitude of the signal received.