Abstract: A cruise speed control apparatus for aircraft wherein small differences between the target Mach command and the actual Mach number of the aircraft are used to displace the aircraft from its reference altitude to either increase or decrease actual Mach number in the short term. Long term differences are corrected through a special isolation filter to separate the engine control loop and pitch control loop dynamics and an integration technique to adjust the automatic throttles about a thrust target for the commanded Mach.Large differences between the target Mach and the actual Mach or large changes in the commanded Mach are compensated for by a non-linear gain that effectively increases or decreases the target thrust to cause the aircraft to accelerate or decelerate to the commanded Mach.

Abstract: A digital signal detector utilizing a detected input digital signal derived from a reference square wave and a received pulse train to establish phase and frequency variations between the reference signal and the received signal. The detected signal and the reference signal are coupled to up-down counters wherein overflow counts from preset values are obtained which are representative of the frequency and phase difference between the reference and received signals. These overflow counts are utilized to establish phase and frequency error correction signals which may be coupled to control the reference oscillator to provide frequency and phase lock between the reference and received signals.

Abstract: A plurality of concentric sealing rings on the face of a static sealing surface provides a positive seal when used with Teflon film or like materials that have a tendency to cold flow under pressure into recesses created by the concentric sealing rings.

Abstract: A system for the secure and rapid acquisition of a transmitted acquisition composite code composed from acquisition component codes. The acquisition composite code may, for example, be composed in accordance with a Boolean majority voting rule. Reference component codes that correlate respectively with the acquisition component codes are combined to provide a verification composite code that correlates with the acquisition composite code only when all of the reference component codes in the verification code are each in alignment with the corresponding acquisition component codes in the acquisition composite code. The verification code may, for example, be composed in accordance with a modulo-2 addition rule. Initially, the reference component codes are individually brought into alignment with the transmitted signal during the acquisition thereof.

Abstract: An apparatus for providing asymmetrical torque-switching for an aircraft autopilot. The invention provides an increased amount of available pitch servo torque at high altitude. The direction of pitch of the aircraft is sensed. An increased amount of torque is provided for the pitch-up direction thereby providing more positive control of the aircraft.

Abstract: A battery powered optical sensor, capable of functioning for a period of time approximately equal to the shelf life of the battery, utilizes an LED driven by an optical transducer and biased by the battery at a level that exceeds the shot noise level of the LED by the dynamic range of the sensor.

Abstract: A variable coupler fiberoptic sensor in which a fused, tapered, biconical directional fiberoptic coupler is encapsulated in a stress birefringent medium whose index of refraction changes with applied stress.The ratio of power in the output fibers of the directional coupler varies with the change of index of refraction of the encapsulating medium as stress is applied to the medium.

Abstract: A cathode ray tube provides a raster can symbol display superimposed on a stroke vector display, with selected regions of the stroke vector display preferentially masked in response to priority instructions. Stroke vector priority data is loaded into a full-field bit-mapped memory by a raster symbol generator and used to provide a stroke vector masking signal in synchronism with the picture elements of the raster scan. The system provides efficient generation of dynamic stroke priority areas by utilizing the repetitive nature of the raster scan to load the stroke priority full-field bit-mapped memory without requiring corresponding processor intervention.

Abstract: Convergence correction for a delta-gun CRT at all locations on the CRT screen is accomplished by separately implementing the general equation for convergence in that coordinate system peculiar to each of the gun's location relative to the screen and modifying the equation coefficients in each of its four quadrants to effect convergence in that quadrant. The quadrants of each of the gun's coordinate system is the same as the quadrants of the CRT screen thereby allowing each of the coefficients to be changed or adjusted only when the terms it multiplies is zero. Complete convergence correction for the entire screen may be accomplished using only nine screen locations. A unique triangular convergence symbol corresponding to the gun locations is placed at each of these nine locations to adjust the equation coefficients, each leg of the convergence symbol being of a color which optimizes the viewability of the convergence of a particular gun.

Abstract: Deceleration control apparatus for an aircraft having an automatic altitude capture and hold system and an airspeed hold system, both systems controlled by controlling pitch attitude wherein during a descent from a higher altitude under airspeed-on-pitch control with throttle set at idle thrust, and at some existing negative altitude rate, a slower speed is commanded, a synthetic altitude based on the existing descent rate is computed and the attitude capture and hold system operation is switched into control in place of the airspeed on pitch control to cause the aircraft to flare toward the synthetic altitude. The resultant loss of airspeed, i.e., craft deceleration, during the altitude capture flare is monitored and when the commanded airspeed reduction is achieved, the airspeed-on-pitch control is resumed to thereby hold the commanded lower airspeed.

Abstract: An apparatus for converting angular position to a linear voltage. A continuous element dual wiper potentiometer provides triangular waveforms 90.degree. apart to a waveform conversion circuit which generates a linear positive going ramp waveform in response to the angular position of the potentiometer wipers.

Abstract: A color cathode ray tube has raster scan color zones defined by X and Y positional signals derived from a stroke vector generator and stored in a digital memory. Raster scan and stroke vector displays are alternately presented in a hybrid display. The display face of the tube is scanned by a plurality of raster lines and a color transition point is defined by the intersection of a stroke vector with a raster line. The X and Y addresses of the intersection points define the raster line, pixel element, and color at the transition point. The system is arranged so that the X and Y addresses are provided by the stroke vector generator in synchronous relation with the color transition points, and read into memory during the stroke vector refresh period. During the raster scan refresh period, the memory contents are recalled in synchronism with the raster scan, passed through a digital to analog converter, and then applied to the display tube to provide filled-in color zones superposed on the stroke vector display.

Abstract: An apparatus for providing a signal representative of armature displacement in a magnetic bearing assembly for a magnetic suspension system, of the type having a force sensor applied in a closed loop to provide a linear response with respect to an input force command signal. Signals representative of currents applied to the magnetizing coils and of the sensed force are used to derive the armature displacement signal. The signal so derived is applied to modulate the magnetic flux and obviates the need for proximity devices for sensing armature displacement. A circuit for generating the armature displacement signal is provided.

Abstract: A helicopter flight control system employs coupled torque limiters in the rotor cyclic pitch axis and collective pitch axis for airspeed and vertical path control, respectively. When the collective torque limit is reached, the cyclic pitch axis is automatically transferred to favor vertical path control. A synchronizer circuit is provided for assuring smooth acceleration transition to reduce accrued airspeed errors when the engine torque limit is no longer commanded.

Abstract: Apparatus for assessing maneuvers of a first vehicle (6) so fitted relative to other vehicles (58, 68, 71-74) comprises sensing means for providing signals representative of the positions and velocities of the other vehicles relative to the first vehicle (6), computing means responsive to said signals for computing symbology respectively associated with the other vehicles, and display means coupled to the computing means for displaying the symbology relative to the position of the first vehicle, thereby providing indicia to assess maneuvers of the first vehicle which will avoid collision with the other vehicles, and which will ensure that the first vehicle will not pass closer to the other vehicles than a predetermined distance for all relative positions and velocities thereof, the symbology associated with each of the other vehicles in all encounter circumstances comprises at least a final escape point (FEP) (40) which, if reached by the first vehicle (6), will allow the first vehicle still to avoid the asso

Abstract: An automatic flight control system that is software fault tolerant fail operational in response to a first generic failure utilizes two independent subsystems each including a dual channel flight control computer. One channel in each flight control computer includes a digital processor and the other channel includes two digital processors. Cross channel monitoring is included in each flight control computer to discern disagreements between the outputs of the channels. If disagreement occurs between one of the two processing elements in the channel including two processing elements and the processing element of the channel having one processing element, the involved processing element in the two-element channel is disabled. If both processing elements in the two element channel disagree with the processing element in the other channel, the subsystem is disabled. All of the processing elements perform identical tasks.

Abstract: A dielectric trough waveguide antenna composed of a metallic guide having a dielectric substrate covering the bottom of the guide and a plurality metal radiators placed periodically on the dielectric at the dielectric-air interface provides a low loss antenna suitable for millimeter wave applications.

Abstract: A communication bus user design that significantly reduces the likelihood of bus disablement. Request to transmit received by a user are validated in the communications processor and by an interlock circuit. Logic signals generated in response to the two validations are coupled to an AND gate, wherefrom an enabling signal is coupled to an amplifier when the two logic signals coincide. Communications signals from the communications processor are thereafter coupled via the amplifier to the bus.

Abstract: Strong narrowband signals interfering with the reception of a desired broadband signal in systems such as spread spectrum systems are continuously suppressed by converting the received signal to a frequency-domain representation thereof wherein strong narrowband interference components appear as strong impulse components. These impulsive components are blanked or clipped at a level that is a function of the average magnitude of the input signal. Resulting suppressed frequency-domain signals are reconverted to time-domain signals that are then available for further processing by conventional broadband signal receivers.

Abstract: An improved flight control system for initiating and thereafter controlling the automatic capture of a preselected altitude is described. At any point in the flight and in any autopilot pitch submode, the remaining time before an altitude capture is to commence is computed and used as a limiting signal such that the aircraft is precisely aligned with the commanded capture flight path when the capture maneuver commences thereby obviating mode to mode transients. The aircraft's altitude rate is continuously monitored during the capture maneuver and the flight path command is automatically altered between asymptotic and circular paths to assure that the acceleration normal to the flight path will not exceed a predetermined value while at the same time allowing a timely altitude capture.