Abstract: The digital-to-analog converter comprises an R-2R ladder network with bit controlled current steering switches connecting the legs of the ladder network to first and second current buses. First and second current-to-voltage converters are connected to the current buses respectively, the second current-to-voltage converter being connected through a switch to the input of the first current-to-voltage converter. A uni-polar/bi-polar control signal renders the switch conductive or non-conductive in accordance with the data format desired. The digital-to-analog converter is also utilized in a successive approximation analog-to-digital converter.

Abstract: A color cathode ray tube display apparatus particularly for use under a wide range of ambient light conditions, such as in an aircraft cockpit, wherein each of the primary color phosphors has a unique brightness versus cathode drive characteristic, which characteristic also is dependent upon whether the displayed information is raster written or stroke written and wherein such characteristics also may vary from tube to tube. The output of at least one cockpit ambient light sensor in addition to a pilot selected brightness is used on a continuous basis to calculate a reference brightness level for the sensed ambient brightness conditions and display writing mode, this reference brightness level being used to calculate the corresponding brightness level for each of the primary color components of the commanded symbology color and concomitant drive voltages to the CRT's cathode or cathodes.

Abstract: The flight path transition control apparatus provides a roll attitude command to control the aircraft to execute an exponential transition path to a predetermined course in accordance with the exponential control law Y+KY where Y is the lateral displacement of the aircraft from the predetermined course, Y is the rate of change of the lateral displacement and K is a time constant of the system. A predictive roll command .phi..sub.p is generated in accordance with ##EQU1## where V.sub.g is the aircraft ground speed,TAE is the track angle error of the aircraft with respect to the predetermined course,TAE.sub.0 is the track angle error of the aircraft with respect to the predetermined course at capture maneuver initiation,g is the gravitational constant, andt is the elapsed time following capture initiation.The predictive roll command .phi..sub.p is combined with the exponential control law to provide the aircraft roll attitude command .phi..sub.c =.phi..sub.

Abstract: A detector for determining whether the time duration between a positive and a negative peak of a waveform is greater or less than a predetermined time interval comprises a delay line for delaying the waveform by the predetermined time interval. A peak detector of a first polarity for detecting the first occurring peak of the waveform is responsive to the delayed waveform to provide a signal upon the occurrence of the first occurring peak thereof. A peak detector of a second polarity for detecting the second occurring peak of the waveform is responsive to the undelayed waveform for providing a signal upon the occurrence of the second occurring peak thereof. A time sequence comparator provides a first output indication when the signal from the first peak detector occurs prior to the signal from the second peak detector and a second output indication when the signal from the second peak detector occurs prior to the signal from the first peak detector.

Abstract: The interleaved dipulse sequence generating apparatus decomposes the data pulses of a data transmission or recording channel into pairs of spaced apart subpulses denoted as dipulses. The dipulses are interleaved or nested with respect to each other and without interference therebetween to provide an interleaved dipulse sequence signal which is conveyed on the channel.

Abstract: The outputs of a three-wire synchro are applied to a multiplexer which provides the multiplexed synchro outputs to an amplifier and demodulator. The demodulated synchro outputs are applied to a demultiplexer whose outputs are filtered to provide demodulated d.c. voltages corresponding to the synchro output signals. The demodulated d.c. voltages are applied to a conversion circuit for providing the sine and cosine of the angular position of the three-wire synchro device. The multiplexer, demultiplexer and demodulator are synchronized by the synchro a.c. reference signal.

Abstract: The transducer for perpendicular magnetic recording comprises a core of high permeability material having a recording pole and a flux return pole spaced apart and connected by an intermediate member forming an inverted generally U-shaped core. The cross sectional area of the flux return pole is substantially greater than that of the recording pole. Current applied to a coil wound around the recording pole generates flux for recording on the magnetic medium. A similarly shaped second core may be disposed on the opposite side of the medium with respect to the first core for providing a flux return path for the first core. A sub-core of high permeability material mounted on the flux return pole forms a gap with the recording pole to provide a ring-type head for data recovery. Current applied to a coil wound on the sub-core saturates the sub-core to render it ineffective during perpendicular magnetic writing.

Abstract: A synchro resolver angular position sensor provides the sine and cosine of angular position by applying a square wave excitation to the resolver stator winding. The corresponding square wave outputs of the sine and cosine windings of the resolver rotor are sampled in time synchronism with the excitation at a predetermined time phase of the square wave excitation cycle. The sampled sine and cosine amplitudes are converted into digital format via an analog-to-digital converter for application to a digital processor. The upper corners of the positively-going leading edges and the lower corners of the negatively-going leading edges of the square wave excitation waveform are rounded to minimize ringing of the sine and cosine square wave outputs from the resolver.

Abstract: Apparatus for providing an integrated display of flight instrument parameters on the screen of a single cathode ray tube is presented. The synthetically generated symbology provides the pilot with an integrated display of substantially all aircraft attitude and flight path command and control parameters including attitude and magnetic heading, barometric and radiometric attitude, vertical spread, critical take-off speeds, true airspeed and Mach airspeed, flight path angle, flight director path control commands, and mode annunciation for the flight director and automatic pilot systems.

Abstract: Decision and control logic for use in digital computers that operate in cycles provides binary valued decision signals for effecting decisional control within the computer such as that utilized in conditional branching. The decision signals are provided in accordance with binary valued control functions of binary valued static and dynamic control variables utilized in the computer. The dynamic control variables are available in a computer cycle subsequent to the availability of the static variables and represent conditions of various components of the computer. Truth tables of the control functions are stored in logic function memories addressed by logic function selection control fields of computer control words, the control fields selectively addressing the truth tables in accordance with the desired functions.

Abstract: A complete frame of radar data is stored in radar real time addressed in accordance with antenna azimuth. The PPI rotating display scan is generated by deflecting the beam along the azimuth sweeps thereof under control of X-rate and Y-rate signals provided for each sweep. The X-rate and Y-rate signals are applied sequentially to X and Y binary rate multipliers which generate clock signals at a frequency proportional to the rate signals. The clock signals are applied to X and Y position counters respectively for generating the X and Y deflection signals via digital-to-analog converters. Sequential application of the X and Y rate signals to the X and Y rate multipliers generates the rotating scan. The radar data stored in memory is accessed in accordance with the azimuth address in synchronism with the generation of the azimuth display sweeps. The stored data provides the video signal for the display tube so as to generate the radar display. The rotating scan is generated in non-real radar time at a rapid rate.

Abstract: Symbology is written on a radar plan position indicator display with a rotating beam deflection field. The PPI radar range is quantized into range increments and digital data representative of the symbology to be written are inserted into a shift register which is clocked in synchronism with the range sweeps to provide interleaved digital data to the video input of the display. The normal radar video data is combined with the symbology data so that the symbology and normal radar returns are simultaneously written in real time. A portion of the symbology generating apparatus provides a manual acquisition marker comprising a range ring and an azimuth geometric figure. A range switch gates a clock pulse signal into a range up/down counter for incrementing and decrementing the number therein, the digital output of the counter being representative of the range of the range ring.

Abstract: The disclosed SQUID (superconducting Quantum Interference Device) comprises two superposed superconductive layers with an insulating layer therebetween. A plurality of holes through the insulating layer filled with superconductive material form weak-links between the superconductive layers. One or more control lines superposed with respect to the superconductive layers provide magnetic flux through the area between the weak-links to control the zero voltage supercurrent flowing through the weak-links from one of the superconductive layers to the other thereby providing the switching function for Josephson superconductive circuits.

Abstract: A Josephson tunnel junction device having niobium nitride superconductive electrodes includes a polycrystalline semiconductor tunnelling barrier therebetween comprised of silicon, germanium or an alloy thereof preferably deposited on the lower superconductive electrodes by chemical vapor deposition. The barrier height of the junction is precisely controlled by precision doping of the semiconductor material.

Abstract: A computer which is configured to perform its operations in overlapped fashion. During each computer cycle the next instruction is fetched, the function designated by the previous instruction is executed, and values are stored that were computed with respect to the instruction previous to the one being executed. Thus a three-way overlap is effected. To minimize time penalties due to conditional branches and jumps, each instruction word includes two next instruction address fields, two function fields and two deferred action fields. The computer includes decision logic for providing binary decision signals for conditionally selecting one of the fields from each of the next address fields, the function fields and the deferred action fields thereby conditionally fetching the next instruction, conditionally selecting the function to be performed and conditionally storing values during the same cycle in accordance with the decision signals.

Abstract: A microprogrammable CPU for a computer utilizes an architecture wherein macro instructions of the computer repertoire are executed by micro instruction routines stored in a control store memory. The micro instruction routines are comprised of micro instruction words for controlling the micro operations to be performed in executing the macro instructions. The CPU includes a plurality of local processors each configured to perform a plurality of the micro operations. A macro instruction fetched into the macro instruction register of the computer addresses the corresponding micro instruction routine in the control store memory and the plurality of local processors operate concurrently to simultaneously perform the micro instructions of the routine on behalf of the fetched macro instruction. Thus a stream of macro instructions flowing through the macro instruction register is decomposed into a plurality of concurrently executed micro instruction streams flowing through the respective local processors.

Abstract: A digital magnetic recording system is disclosed that utilizes partial response signalling to achieve the Nyquist data pulse rate with minimum bandwidth. A. C. bias is introduced to linearize the magnetic medium which, inter alis, permits reliable multilevel (greater than 2) data storage without impairing data accessibility. Preferably Class IV partial response is utilized with one or more sinusoidal lobes in the data frequency spectrum. The basic binary data to be stored is converted to, for example, ternary and the ternary data is precoded. The precoded ternary data is recorded on the magnetic medium via an interleaved dipulse sequence having a spectral null slightly outside the data frequency band. A pilot tone is inserted at the spectral null for timing recovery and automatic gain control.

Abstract: Input/output (I/O) apparatus for a system is disclosed utilizing a digital processor for entering analog, digital and discrete data into the processor and receiving analog, digital and discrete data from the processor via an I/O data bus. A plurality of analog data signals are applied sequentially to an analog to digital converter via an analog input multiplexer. The resultant digital data are applied in bit parallel fashion to predetermined bits of the I/O data bus reserved for the input and output of analog data. Digital and discrete data is entered with the analog data by shifting the data from each of the digital and discrete data sources in bit parallel fashion into associated shift registers. The contents of the registers are shifted serially into respective predetermined bits of the data bus reserved for the input and output of the digital or discrete data.

Abstract: The disclosed SQUID (Superconducting Quantum Interference Device) comprises two superposed superconductive layers with an insulating layer therebetween. A plurality of holes through the insulating layer filled with non-superconductive material form weak-links between the superconductive layers by the superconductive proximity effect. One or more control lines superposed with respect to the superconductive layers provide magnetic flux through the area between the weak-links to control the zero voltage supercurrent flowing through the weak-links from one of the superconductive layers to the other thereby providing the switching function for Josephson superconductive circuits. The non-superconductive material forming the weak-links in the holes provides, inter alia, favorable impedance characteristics for the device.

Abstract: A Josephson tunnel junction device having niobium superconductive electrodes with an amorphous hydrogenated semiconductor tunnelling barrier therebetween comprised of silicon or germanium or an alloy thereof supports an unusually high critical current density. Barrier dopants provide a further increase in the critical current density. The barrier is deposited by rf-sputtering in an atmosphere containing hydrogen.