Abstract: A solder paste applicator for applying solder to a selected area of a printed circuit board on which electronic components are mounted. The applicator includes a housing with a plate mounted in one end. The plate has a pattern of holes through it corresponding to the pattern of solder to be applied to the board. The housing has movable legs mounted to the outer surface for positioning the plate a distance from the surface of the board which corresponds to the thickness of the solder to be applied. The solder is held in a reservoir above the patterned plate. A piston is positioned in the housing and is pushed against the reservoir for dispensing the solder.

Abstract: A phase detector for a phase locked loop (PLL) to be employed in a wideband synthesizer generates a ramp waveform at an output. The ramp waveform has a positive slope during the reference signal; when a sample pulse is received by the circuitry, the slope of the ramp is changed to a negative slope. Hence, the output of the detector will be negative or positive depending upon the difference in phase between the reference and sample frequencies. The ramp voltage is sampled and held by a suitable circuit which provides an error signal for controlling a VCO.

Abstract: An image intensifier tube having an electromagnetic interference protection arrangement. The protection is accomplished by shielding the tube and filtering the power supply. Shielding is performed by means of a conductive metallic coating which surrounds the image intensifier tube housing. Filtering is accomplished by using capacitors to short the interference to ground.

Abstract: A composite buffer layer is formed with a layer of GaAs on a semi-insulating GaAs substrate. Next a short period superlattice is formed followed by another GaAs layer. A layer of GaAlAs is then provided such that the Ai content and no doping followed by an intrinsic GaAs layer. The intrinsic GaAs layer is the active layer which serves as a channel.

Abstract: A fail-safe port apparatus includes a low loss liquid crystal optical switching device providing first and second light paths, the first path providing a failure, or default, mode path and the second path providing an operating mode.

Abstract: There is disclosed a high frequency communication system of the type employing a high frequency terminal which terminal can transmit a processed signal in a transmitting mode or process a received signal in a receiving mode which terminal includes a first subsystem for voice processing, including a processor responsive to voice signals to provide a linear predictive coded voice signal at a given data rate which signal is coupled to a data modem subsystem that digitally encrypts said voice signal which data modem subsystem is coupled to a modem processor subsystem capable of processing said encrypted signal for providing frequency hopping, feedback equalization, intersymbol interference cancellation, error correction and interleaving to provide a transmitted signal which is relatively immune to jamming during said transmitting mode which includes a convolutional encoder means included in said modem processor subsystem responsive to said encrypted signal to provide a convoluted signal at a higher data rate than

Abstract: A microchannel electron multiplier is formed by placing into a glass tube a plurality of bundles optical fibers, each having an etchable glass core and a glass cladding which is non-etchable when subjected to the conditions used for etching the core material. The fiber bundles located around the inside edge of the glass tube are replaced by support fibers having both a core and a cladding of a material which is non-etchable under the above-described conditions. The assembly of the tube, bundles and support fibers is heated to fuse the tube, bundles and support fibers together. The etchable core material is then removed and the assembly sliced into wafers. The inner surface of each of the claddings which bound the channel formed after removal of the core material is rendered electron emissive by reduction of the lead oxide by hydrogen gas. Metal films are deposited onto the opposed surfaces of each of the wafers to form contacts.

Abstract: A first plurality of spaced radar ground systems and a second plurality of radar ground systems positioned in between adjacent pairs of the first systems. The first systems, when employed in an early warning radar chain, preferably have antennas which are mechanically rotatable. The second systems are then provided with phased arrays to enable two-way communication without it being necessary to stop any scanning movement of a corresponding first system antenna.

Abstract: An N-way redundant switch is implemented through the use of serial and parallel redundancy for providing redundancy in both ON and OFF operating modes.

Abstract: A method and apparatus for noise suppression for speech recognition systems which employs the principle of a least means square estimation which is implemented with conditional expected values. Essentially, according to this method, one computes a series of optimal estimators which estimators and their variances are then employed to implement a noise immune metric. This noise immune metric enables the system to substitute a noisy distance with an expected value which value is calculated according to combined speech and noise data which occurs in the bandpass filter domain. Thus the system can be used with any set of speech parameters and is relatively independent of a specific speech recognition apparatus structure.

Abstract: An automatic speech recognition system employs parallel syntaxes with a first syntax operative to compare keyword templates with incoming speech over a given time interval and with a second syntax in parallel with the first and operative to compare filler templates with incoming speech over the same interval. Based on the best comparisons in each syntax a likelihood probability ratio is computed and compared against a selected threshold for determining whether the speech contains a valid phrase or keyword as compared to an undesirable utterance.

Abstract: A method of accurately determining the temperature of a thin layer of bandgap material without requiring contact to the layer involves the use of optical radiation through the layer and the detection of optical absorption by the layer. The relationship between the temperature varying bandgap energy and the resulting optical absorption characteristics provides an indication of temperature independent of ambient temperature. Apparatus for performing high quality temperature detection and control is also provided.

Abstract: An analog to digital converter for a speech signal is implemented in modules to allow for changes in bit rate and changes in bit stream length according to requirements of the digital transmission system. A pre-emphasis circuit provides an array of pre-emphasized speech samples which are stored in memory. A linear predictive coder provides an array of reflection coefficients and an array of filter coefficients. A pulse processor receives the speech samples and filter coefficients and generates speech amplitude and location signals. These signals are multiplied to generate quantized speech samples. The quantized speech samples and reflection coefficients are provided to a buffer which provides an output signal of a proper bit stream length and bit rate for the digital transmission system.

Abstract: A structure associated with a ceramic envelope gas filled electron tube whereby a series of concentric holes are formed through grid radiator rings which thus simulates the outer neutral gas region of a typical glass envelope tube structure. In this manner, one has created a neutral non-ionized gas flow path which shunts the main discharge in such a thyratron and which is contained within the metal internal axial structure. The apertures, as formed in the grid radiator rings, thereby provide a source path for neutral molecular hydrogen from the gas reservoir located at the base of the tube to allow the gas to be directed to the anode/grid region of the tube, where electrons are pumped and the gas is collisionally ionized. The effect serves to enhance the maximum thyratron operating frequency by allowing cool neutral gas molecules to flow into the gap region through the parallel path and then into the discharge volume of the ceramic thyratron tube.

Abstract: There is disclosed an interface apparatus which enables a radar jamming system to operate in conjunction with a number of different radar warning receivers. The interface enables the jamming apparatus to couple to various types of radar warning receivers and to specify proper blanking intervals for each of the receivers according to the type of blanking required and the operation of such receivers. The system employs a look-through blanking bus which essentially consists of six data lines and a strobe. The data on this bus is fully encoded to provide 64 individual command codes. The command codes are established by the particular RWR and are made available via the interface to the jamming system over a multiplexed bus. This bus operates to initially specify the RWR by determining the various codes which are transmitted by the RWR.

Abstract: Doppler shift generator for use in electronic countermeasures equipment includes analog memory devices which are comprised of acoustic charge transport (ACT) memory devices. Such Doppler shift generators includes a switch which alternately applies an input signal to said first and second analog memory devices. Each analog memory device is responsive to a clock signal to sample data at a first frequency and to output the data at a second frequency. As a result, a Doppler shifted signal is generated whose frequency has been shifted by the difference in the first and second frequencies.

Abstract: A Doppler matched binary pulse compressor having means to initiate operation, means to generate a Doppler matched filter bank, means to compress the pulses from the Doppler matched filter, either linear or soft limited, means to estimate the signal phase in real time and means to select overall optimal filters in real time. The foregoing includes a phase estimator having a quadrant detector and means to scale the quadrature components while preserving the signal phase, means to reduce accuracy computations to 45.degree. or less of the first quadrant, and means to reconstruct the phase to place the signal in the proper quadrant.

Abstract: The subject invention employs a system integrated fault-tree analysis (SIFTAN) which has the unique ability to detect all latent hardware and software design defects that could cause unanticipated critical failure of a complex software controlled electronic system. This new approach modifies and then integrates two existing system analysis techniques-namely, hardware fault-tree analysis (HFTA) and software fault-tree analysis (SFTA). The resultant integrated technique is identified as SIFTAN for system integrated fault-tree analysis. Through its integrated hardware/software scope and its critical failure focus, SIFTAN has unique potential to solve the essential analytical limitation behind the software reliability problem. The system exceeds the scope of all current system analysis techniques by providing a system free from all potential critical specification hardware or software design errors.

Abstract: A direct device-to-connector interconnection includes a plurality of conductive strips affixed to a support member, each strip being cooperatively sized and aligned to establish a direct fanned out connection between a bonding pad and an external connector.

Abstract: A first plurality of spaced radar ground systems and a second plurality of radar ground systems positioned in between adjacent pairs of the first systems. The first systems, when employed in an early warning radar chain, preferably have antennas which are mechanically rotatable. The second systems are then provided with phased arrays to enable two-way communication without it being necessary to stop any scanning movement of a corresponding first system antenna.