Abstract: A multilayer printed circuit board (10) is provided with vertical circuit traces (51-54) which are readily accessible by mechanical means, by first creating vias at the locations of the vertical circuit traces (51-54). An opening (59) is then bored in a manner that the perimeter of the opening (59) intercepts the vias. The remaining plating material on the vias forms the vertical circuit traces (51-54), which are thereby established along the perimeter of the opening (59).This technique utilizes procedures which are readily adaptable to present multilayer printed circuit board manufacturing techniques and which effect a low cost and reliable connection. Furthermore, the vertical circuit traces (51-54) are readily accessible for mechanical broaching and can be formed in a relatively high-density configuration.

Abstract: A coupling shaft couples driving and driven shafts which are subject to relative misalignment. The coupling shaft has crowned male polygonal profiles on both of its ends, and which ends mate directly with corresponding female polygonal profiles carried by the driving and driven shafts. The crowned male profiles permit the coupling arrangement to act in a hinge like manner to accommodate the misalignment. Non-metallic bushings and adapters may be interposed between the coupling shaft and the driving and driven shafts to eliminate metal to metal contact and to thereby eliminate fretting and metal wear which would otherwise occur.

Abstract: A flight recorder (11) for a vehicle such as an airborne vehicle is provided in which various data is recorded, along with on-board time data (from 38) in order to be processed by ground based equipment (13). The on-board time data is synchronized by using a telemetry signal (DT) which is received by a ground based tracking system so that the timing of the events recorded by the flight recorder (11) may be synchronized with the timing of events recorded by the ground based tracking system. This combined data is provided to the ground based equipment (13) in order that the data at (12) obtained on-board the vehicle can be analyzed. By the use of digital techniques, various measurements, such as acceleration and angular rate may be accurately stored and reproduced. This arrangement reduces repeat costs for multiple tests and increases reliability of test data.

Abstract: A proportional fuel fuel control (11) regulates the fuel flow (Wf) from a hydromechanical unit (36) based upon an error signal (E) representing the difference between a demanded speed signal (Nd) and an actual speed signal (Nh). The demanded speed signal (Nd) is generated by an integrator (32) as the time integral of the least of a plurality of acceleration terms (Aa, Ab, Ac, Ad) selected by a select low gate (38). The demanded acceleration term (Aa) is generated by junction (26) as the difference between the demanded signal (Nd) and a scheduled speed signal (Ngs). Stress acceleration terms (Ac, Ad) are generated by junctions (48, 50) and scheduling means (42, 44) which form stress limiter circuits. A stall acceleration term (Ab, is generated by a junction (46) and a scheduling means (40) which form a stall prevention feature.

Abstract: A multi-phase undervoltage detection circuit is disclosed wherein a multi-phase input voltage is compared to a reference. If the peak level of the input voltage is above the reference, a capacitor is discharged. If the voltage of any one of the phases is below the reference, the capacitor charges above the level of the input to a flip-flop. At the same time the voltage of another of the phases clocks the flip-flop. Since the input of the flip-flop is "high" when it is clocked, it changes states and its output goes "low" which provides a circuit output indicative of an undervoltage condition. If no undervoltage condition exists, the flip-flop will not change states and the circuit output is indicative of a non-undervoltage condition.

Abstract: A variable digital delay circuit is disclosed which utilizes a shift register to periodically sample a signal to be delayed and after a predetermined number of samples are collected as a group of zeros and ones making up a binary word the word is stored in parallel in a memory. After each binary word is stored in a memory a binary word previously stored in the memory is read out into a buffer store from which each individual bit is sequentially read out using a multiplexer at the same rate that the bits were originally taken to thereby recreate the original signal samples. The time delay is determined by how long the previously stored binary word being read out has been stored in the memory.

Abstract: A fail-safe solenoid switching mechanism (11) includes separate solenoids (17,18) for switchings to "armed" and "safed" statuses. A manually operated safing mechanism (19) has a capability of overriding the solenoids (17,18) to establish the switching mechanism (11) in the "safed" status. The manually operated safing mechanism (19) is operated by a special tool (41), which is retained by the switching mechanism (11) whenever the manually operated safing mechanism (19) is engaged. The manually operated safing mechanism (19) is held in engagement by a catch (22) whenever the solenoid (17) for arming is powered, thereby preventing the specialized tool from being removed and the switching mechanism (11) from inadvertently switching to the "armed" status. Further status indications are provided by a flag (54) which can be used to directly read the status of the switching assembly (11).The switching assembly (11) uses a reciprocating switch (15) to establish make-or-break connections.

Abstract: A moving map display is provided to represent the location of a vehicle such as an aircraft on a video display of a map. Map images are scanned by a remote pickup unit (40) using flying spot scanning techniques to scan transparencies (51) of sections of the map. In order to increase the resolution of map images, each transparency (51) is divided into a plurality of sections and an image of the flying spot from a CRT (45) is superimposed simultaneously onto the nine sections, using an optical tunnel. In order to scan only the desired portions of these images and in order to produce a coherent display, the images are selectively gated "on", electronically or by using light shuttering techniques. In the preferred embodiment, four of a group of nine images are used to create a given display, although other combinations are possible.The resultant display is a composite video modulated raster derived from the scanned images on the slide (51).

Abstract: A microstrip antenna with a linearly polarized radiating patch is varied in resonant frequency by an electronic tuning technique. A dc bias voltage is combined with the excitation signal to regulate the capacitance of a varactor diode mounted in the antenna structure. In one embodiment the varactor is in shunt with a half wave open circuited radiator and adds electrical length to the antenna, while in another embodiment the varactor is in series with a shorted quarter wave radiator and subtracts electrical length therefrom.

Abstract: An interface (10) between a first (MC, 30) and second (SC) computer employs a multiplexer (46) and a coupler (48, 50). The first (MC, 30) and second (SC) computers have a first (LA/B, LEX0-15) and second (CX1-21, CA1-15) plurality of information lines, respectively. These computers also each have a group of control lines (36, 42). The multiplexer (46) is connected to the first and second plurality of information lines (LA/B, LEX0-15, CX1-21, CA1-15). The multiplexer (46) is operable to separately switch each of a predetermined group (LEX12-15) within the first plurality (LA/B, LEX0-15) between either member of a different corresponding pair within the second plurality (CX1-21, CA1-15). The multiplexer (46) is also connected to at least one (ESELCX) of the control lines (36) of the first computer (MC, 30). The multiplexer (46) can switch the predetermined group (LEX12-15) in response to a signal on the control lines (ESELCX) of the first computer (MC, 30).

Abstract: A frequency translator receives an input frequency signal and an offset frequency signal, and processes the signals digitally in order to obtain an output from a multiplexer. Pulse trains derived from the input frequency are provided to an N-bit shift register. The outputs from the shift register are provided to a multiplexer which is controlled by count signals from the offset frequency. The multiplexer provides, as its output, a single sideband output at a frequency equal to (f.sub.c -f.sub.os)/N, or (f.sub.c +f.sub.os)/N.

Abstract: A system for transmitting an EPR (Engine Pressure Ratio) from a gas turbine is provided with a resolver component (30) which modifies the EPR in accordance with variations in the optimum EPR for a particular turbine under particular conditions. The information from an EPR gauge is transmitted by a synchro transmitter, and is received by a differential transmitter (31) associated with the particular engine being monitored. The differential transmitter (31) is adjusted in accordance with pressure (at 33) and temperature (at 56) conditions in order to provide an EPR reading which is compensated in accordance with actual conditions of pressure and temperature. The differential transmitter (31) is also adjusted (at 45) in order to provide an output which is further varied in accordance with a variation in the optimum EPR under standard conditions for the particular turbine associated with the differential transmitter.

Abstract: Printed Circuit Board Testing Apparatus is disclosed which utilizes a "bed of nails" of contacts with conductive probes mounted in an insulating plate on a grid of 0.050 inch spacing to make a plurality of electrical contacts with a printed circuit board under test. This large number of contacts are all connected to the edge of a plurality of printed circuit boards mounted perpendicular to the back of the plate. Paths on each of these printed circuit boards electrically connect the probes of the contacts to a large scale integrated circuit chip on which are a plurality of analog switches each controlled by one bit of a binary word stored in a multi-stage shift register also on the chip. One side of each switch is connected to a probe while the other side of the switches are tied together in busses to create a multiplexing arrangement to thereby connect ones of the large number of probes to a relatively small number of input/output leads also connected to the printed circuit boards.

Abstract: A video test pattern generator is able to be incrementally adjusted in its number of lines and in its line resolution, and at the same time is able to produce a reference frequency. The reference frequency is established at a selected value and offset from the selected value by an amount necessary to coincide with a multiple of a scan line frequency. This can be accomplished despite changes in scan rate and raster pattern. A stroke generation capability is provided and the system can be utilized with programmable character generation and can produce a high-resolution image with a minimum of hardware. Further advantages include the ability of the system to adapt to new or changed equipment to be tested.

Abstract: A force measuring system is provided in which a force sensitive element (51) includes a movable capacitor plate (21) located between two fixed capacitor plates (19, 20). A pair of jewel bearings (52) are mounted to a support casting (55) and provides support for a force sensitive element (51). The support casting (55) also serves as a support for a hybrid integrated circuit (68) which, in turn, forms a support substrate for one of the fixed plates (19). A second fixed plate (20) may be mounted on the casting (55) via a substrate (69). The hybrid integrated circuit (68) is therefore in close proximity to a capacitor element (19-21). The hybrid circuit (68) provides output power to a torquer coil (37) which centers the force sensitive element (51), with current provided to the torquer coil (37) being indicative of force exerted on the force sensitive element (51).

Abstract: A resonant flyback boost circuit (21) is used to enchance flyback performance by decreasing the time required for completing flyback on systems using a cathode ray tube and a magnetic deflection coil (11). The boost circuit (21) is parallelly connected across the yoke (11) in order to sense a voltage peak which occurs at the initiation of flyback. The voltage peak is used to initiate a control signal for allowing current to pass from a high voltage source (23) to a supplemental boost capacitor (33). When the potential across the supplemental boost capacitor (33) exceeds the potential across the yoke (11), current flows from the supplemental boost capacitor (33), to an isolating diode (40) to the yoke (11), thereby increasing the current flow through the yoke (11) during the allocated flyback period.The boost circuit (21) reduces flyback time while maintaining a high input impendance when boost is not being applied.

Abstract: A proportional fuel fuel control (11) regulates the fuel flow (Wf) from a hydromechanical unit (36) based upon an error signal (E) representing the difference between a demanded speed signal (Nd) and an actual speed signal (Nh). The demanded speed signal (Nd) is generated by an integrator (32) as the time integral of the least of a plurality of acceleration terms (Aa, Ab, Ac, Ad) selected by a select low gate (38). The demanded acceleration term (Aa) is generated by junction (26) as the difference between the demanded signal (Nd) and a scheduled speed signal (Ngs). Stress acceleration terms (Ac, Ad) are generated by junctions (48, 50) and scheduling means (42, 44) which form stress limiter circuits. A stall acceleration term (Ab) is generated by a junction (46) and a scheduling means (40) which forms a stall prevention feature.

Abstract: A Color Separator for a Map Display Video Generator utilizing a Fresnel lens to expand a multicolor light signal output from a point of light scanned map film to a stationary area that entirely fills an input end of a bundle of optical fibers the other end of which bundle is divided into three smaller bundles. The light output from each smaller bundle is first passed through a colored filter to thereby separate the light into the primary colors red, green and blue. The separated light is then converted to an electrical signal by photomultipliers and used to generate a color video signal applied to a color cathode ray tube display to display the map thereon.

Abstract: A method for making a direction sensitive contrast enhancement filter for a shadow mask color cathode ray tube is disclosed to minimize the amplitude of moire interference patterns to unnoticeable or unobjectionable levels. For a particular color cathode ray tube phosphor dot size, the light transmission through a direction sensitive enhancement filter having a given hole size and spacing is determined mathematically. The filter is then moved a number of fixed increments with respect to the phosphor dot and the light transmission is determined for each incremented position. The variation in light transmission as the filter is moved incrementally across the phosphor dot is the data recorded. This procedure is repeated for different hole sizes and different hole spacings and the data graphed to find the minimum light transmission variation. At this minimum light transmission variation moire patterns are reduced to unnoticeable or unobjectional levels.

Abstract: A moving map display used on an aircraft or other moving vehicle is disclosed. Discreet map segments are stored on a video signal storage means and portions of the video signals for several map segments are read from the storage means and combined to create a composite map segment which is displayed within the aircraft or other moving vehicle. A navigation system on the vehicle provides position information to a microprocessor which functions with other circuitry to determine which map segment portions are to be combined to create the composite map segment.