Abstract: A pilot valve suited for use as the first stage of a large hydraulic valve system. The pilot valve virtually eliminates the steady state fluid leakage associated with orifice-based prior art systems. A pair of low noise and long life fluid restrictors are employed having flat openings thereto over which a flexible metal strip is disposed. The ends of the strip adjacent each opening are attached to one edge of rolling members whereby they can be rolled progressively off of and over the openings by an electrically driven actuator. In this manner, fluid flow through the two restrictor paths are controlled simultaneously to change the amount of fluid passing therethrough. Taps are provided in each restrictor for taking out the control fluid flow and pressure which are applied to the main valve as the driving means thereto.

Abstract: In a spread-spectrum direction-finding system, the outputs of the several antenna elements (10a-d) are progressively translated in frequency by a chirped local oscillator (14) and mixers (12a-d) and applied to a two-dimensional dispersive filter (18), which time compresses the results of single-frequency components in the antenna-element outputs to narrow pulses. Limiters (24a-d) remove any strong narrow-band components that are compressed by the dispersive delay line (18) so that further processing to detect a spread-spectrum signal is not degraded by the presence of narrow-band signals. The use of a common two-dimensional delay line (18) to provide the time compression avoids the need to maintain phase tracking among a plurality of separate parallel one-dimensional dispersive delay lines.

Abstract: An optical decoder to permit differentiating between at least two flashing spots displayed on a cathode ray tube screen is provided by a photosensor and an electrical circuit which is responsive to the absence of flashes during a flashing sequence which is different for the two spots and not distinguishable by the naked eye.

Abstract: A signal-acquisition system (10) for a circular antenna array (12) includes a two-dimensional compressive receiver (18) that performs a two-dimensional Fourier transformation in time and position on the outputs of the array. Each of the outputs of the compressive receiver (18) is fed to input ports of several processing units (24), which multiply them by an appropriate time-dependent function. The resultant modified signals are then processed by Butler matrices (30) that together have a matrix of output ports (32). Each output port is associated with a different combination of azimuth and elevation angles. A signal source at given azimuth and elevation angles with respect to the array (12) causes its greatest response in the output port (32) associated with those angles.

Abstract: A pneumatic time delay valve primarily adapted for use in the ejection system of electronic or optical countermeasure devices and the like wherein an explosive squib is employed to create a momentary charge of high pressure gas used to depress the firing pin on the device to activate the device and also to push the device out of an ejection tube. The invention comprises means for splitting the pressurized gas into a first conduit communicating with the firing pin and a second conduit communicating with the device to apply the ejection pressure thereon and a time delay valve disposed within the second conduit for delaying the application of the gas to the device. During the time delay period, a piston is forced down a cylindrical bore forcing metering fluid through an orifice.

Abstract: A frequency-and-direction-finding system (10) employing a circular array (12) performs a two-dimensional Fourier transformation in space and time on the signals from the individual elements. The results of the transformation are fed to multipliers (22) that multiply them by correction factors that are derived from antenna patterns of the array but do not include the bearing-dependent factors in those systems. The result is an ensemble of values whose relative phases represent a spatial frequency proportional to the bearing angle of the source. Accordingly, a second fast-Fourier-transform circuit (26) operating on this ensemble of values produces an output only on an output port corresponding to the bearing angle of the source.

Abstract: A receiver employs fast-Fourier-transform modules to process the received signals in the frequency domain. It samples the input signal at a high sampling rate to cover a broad input bandwidth, but it transforms the sampled input signals in short segments, segments that cover time durations considerably shorter than the duration of the impulse response of the receiver's tuner filter. The transform of the sampled input signal is multiplied by a Gaussian transfer function to reduce the amount of information contained in the signal, and the values of the resultant frequency-domain sequence are reordered in such a manner as to correspond to resampling in the time domain at a slower rate. This results in coverage of the time duration of an input segment by a relatively small number of samples.

Abstract: In a digital communications system, one of two tones is selected for each bit, a first tone for a "0" and a second tone for a "1"; the tones are unique for each bit. The tones for all of the bits of a byte are sent simultaneously, in a burst or pulse. At the receiver, a parametric model-based spectrum analysis is performed to find the constituent frequencies which produced the composite spectrum. This spectrum analysis uses autoregressive parameter estimation techniques to determine the most likely combination of frequency components which would have generated the composite spectrum. The combination of frequency components so found is then decoded to yield the corresponding bit values represented by those frequencies. The use of autoregressive spectral analysis techniques to recover the frequency components in the composite signal provides both bandwidth compression (by virtue of increased resolution) and faster signalling rates in transmitting just such signals.

Abstract: A system for indicating the direction of a source of radio waves received by a circular antenna array (12) includes a Butler matrix (18) that receives the array outputs and feeds the resultant matrix outputs to correction circuits (22) whose transfer functions are the inverses of the direction-independent factors of antenna patterns generated by antenna elements driven at relative phases that advance around the array at rates that complete an integral number of cycles in one circuit of the array. The resultant corrected signals are fed to a compressive receiver (26), which accordingly generates an output on an output port whose position indicates the direction of the source of the signal.

Abstract: A D-type flip-flop (10) receives the D input on an input line (14) of a transfer gate (12) that also receives the flip-flop clock signal. A state gate (20) forwards the transmission-gate output when the signals on two of its input lines (22) and (24) remain true. To reset the flip-flop asynchronously, a false signal is imposed on one of the input lines (22) of the state gate (20). By coordination of a second clock signal, which is applied to a second transmission gate (34), with the reset signal, the reset condition is held until the next clock pulse on the first transmission gate (12). The flip-flop ordinarily operates as a dynamic circuit, but, in order to maintain the reset condition in circumstances in which the reset state is to be maintained for an extended period of time, a latch gate (26) is enabled by a true signal on one of its input lines (32) to feed the reset output of the state gate 20 to one of its input terminals (24 ) so as to latch the flip-flop in the reset state.

Abstract: The effects of impulse noise on the operation of a microprocessor-controlled Loran-C receiver are reduced by muting or attenuating the received signals in the front end of the receiver ahead of the receiver gain during a time period which preceeds the start time of the pulses being tracked. The attenuation is selectively removed after the start time of each pulse being tracked to permit the receiver to perform its time difference of pulse arrival measurements in the normal manner. The attenuation is also selectively removed during those time periods in which the receiver performs its envelope slope, skywave/groundwave and other such samplings. The attenuation is provided by a muting circuit which is controlled by a time gate signal that derives from the microprocessor of the receiver.

Abstract: A mechanism for clamping the leading edge of a sheet to be wrapped around a printing drum for printing in a plurality of colors includes a clip that is movably mounted in the drum so that it can be moved between an open position and a clamping position, the clip being biased to its clamping position. One or more deflectable cams are positioned adjacent to the drum for engagement by the clip. When the drum is rotated in its direction for printing successive colors on the sheet, the clip deflects the cam and remains in its clamping position. However, when the drum is rotated in the opposite direction to discharge a printed sheet, the clip is engaged by the cams and wedged thereby to its open position thereby releasing the printed sheet. The mechanism also includes provision for automatically discharging the printed sheet from the drum to a discharge path adjacent to the drum when the clip is opened.

Abstract: A data stack for storing data at sequential locations in a memory and for transmitting the data in modes defined by commands from a host data processing system. A random access memory stores the data in sequential locations at addresses selected by a state signal generator comprising read only memory. The state generator generates the addresses and read/write control signals for the random access memory in response to the commands from the host system and a previous address provided by the generator.

Abstract: A drive roll 14 carries a gear (60) that engages a reversing gear (58) driven by a planetary gear (56) on a pivot arm (50). The planetary gear (56) is driven by a sun gear (48) that rotates about the pivot axis of the pivot arm (50) and in turn is driven ultimately by a motor (30). A unidirectioal roller clutch (52) is connected between the pivot arm (50) and the sun gear (48) so as to permit relative rotation between the sun gear and the pivot arm in one direction but prevent it in the other direction. As a result, when the sun gear (48) is driven in one direction, it permits the pivot arm to remain in the position in which the planetary gear (56) engages the reversing gear (58). When the sun gear (48) is driven in the other direction, on the other hand, the pivot arm (50) is caused to pivot with rotation at the sun gear (48) to bring the planetary gear (56) out of engagement with the reversing gear (58).

Abstract: A precision microwave delay line fabricated using stripline techniques, but having features of a coaxial transmission line. The delay line is assembled from three pieces: a center board, an upper housing, and a lower housing. The center board is a nonconductive substrate with a stripline conductor. The stripline conductor defines a transmission path. The housings are made of conductive material. A channel is formed on the inner surface of each of the housings. The channels are arranged such that when the center board is sandwiched between the housings, the transmission path is contained within a uniform cross-section cavity formed by the channels. The housings are electrically connected to each other through the center board with plated-through holes at locations along the sides of the transmission path.

Abstract: A bit-slice adder circuit for adding a plurality of input numbers in binary form. A tally circuit receives all of the bits from a bit position of all of the numbers and identifies the number of "ones" in that bit position. This information is coupled as address signals to a memory, which also receives, as address signals, carry signals. Each storage location at each address in the memory stores the sum of the carry portion of the location's address and the "ones" portion of the address signals from the tally circuit. The least significant bit of the addressed storage location is coupled to a shift register, and the remaining bits comprise the carry signals that are coupled to the memory's address input for the next signal from the tally circuit. After all of the bit positions in the input numbers have been coupled through the tally circuit, the sum is generated which comprises the last carry signal concatenated with the bits stored in the shift register.

Abstract: The present invention pertains to an apparatus .[.and method.]., in conjunction with standard monochrome and color television receivers, for the generation, display, manipulation, and use of symbols or geometric figures upon the screen of the television receivers for the purpose of .[.training simulation, for.]. playing games.[., and for engaging in other activities.]. by one or more participants. The invention comprises in one embodiment a control unit, .Iadd.an apparatus .Iaddend.connecting .[.means.]. .Iadd.the control unit to the television receiver .Iaddend.and in some applications a television screen overlay mask utilized in conjunction with a standard television receiver. The control unit includes the control .[.means.]. .Iadd.circuitry.Iaddend., switches and .Iadd.other .Iaddend.electronic circuitry for the generation, manipulation and control of video signals which are to be displayed on the television screen. The connecting .[.means.]. .Iadd.apparatus selectively .Iaddend.

Abstract: The present invention pertains to .[.an apparatus and.]. .Iadd.a .Iaddend.method, in conjunction with standard monochrome and color television receivers, for the generation, display, manipulation, and use of symbols or geometric figures upon the screen of the television receivers for the purpose of .[.training simulation, for.]. playing games.[., and for engaging in other activities.]. by one or more participants. The invention comprises in one embodiment a control unit, connecting elements and in some applications a television screen overlay mask utilized in conjunction with a standard television receiver. The control 10 unit includes the control, switches and electronic circuitry for the generation, manipulation and control of video signals which are to be displayed on the television screen. The connecting elements couple the video signals to the receiver antenna terminals thereby using existing electronic circuits within the receiver to process and display the signals.

Abstract: A hand held paper pager is disclosed in which a transmitted message is displayed in alpha/numeric form by a precessing display which moves the received message across the display in a continuous fashion so that the display need be only large enough to present a relatively small portion of the total message at any given time. In one embodiment a dot matrix LED display is used and is driven by a recirculating shift register memory to provide the precession of the message as a result of the recirculation. In another embodiment the pager may also include a message entry section in which the precessing display is used to present and edit the message prior to transmission either via an acoustic telephone link to a remote transmitter, or directly from a transmitter carried in the pager/encoder package.