Abstract: An agile, spinning spacecraft has a first body portion and a second body portion which is rotatably coupled about a first rotational axis to the first body portion. A pair of planar solar cell arrays are rotatably coupled to the second body portion along a second rotational axis that is preferably orthogonal to the first rotational axis. The first body portion can be spun if desired and the first rotational axis can be directed by an attitude control system to have selected orientations. The solar cell arrays are rotated about the first and second rotational axes in accordance with steering laws which maintain the arrays in an orthogonal relationship with a Sun line.

Abstract: An electromagnetic resonator comprises an interior wall defining a substantially cylindrical cavity having a major axis. The interior wall includes first and second coupling grooves substantially parallel to the major axis. For a lesser level of coupling, the coupling grooves may be shorter than the length of the resonator and/or the second coupling groove may be omitted.

Abstract: The present invention discloses a microwave filter (10) for controlling the degenerate resonant modes of a spherical cavity resonator (12). The spherical cavity resonator (12) has an inner spherical surface (14) which defines a spherical cavity (16). A first and a second set of tuning elements (18) extend inward from the inner spherical surface (14) of the resonator (12) into the spherical cavity (16). One of the first set of tuning elements is located near an electromagnetic field peak, either a radial electric field peak or a surface magnetic field peak, of at least one of the degenerate modes for tuning a resonance thereof. One of the second set of tuning elements is located between electromagnetic field peaks, either radial electric or surface magnetic field peaks, of degenerate modes in at least one pair of the degenerate modes for intercoupling thereof.

Abstract: A retainer made from a shape memory alloy (SMA) is utilized in a separation device that is particularly useful for space applications. Upon being heated to a restoration temperature, the retainer changes from a constricted state to an expanded state. In its constricted state, the retainer surrounds and captures a plurality of securing segments to secure an object. To release the secured object, the retainer is heated to its restoration temperature with an electrical heater, causing the retainer to return to its expanded state and allow the securing segments to move apart and release the secured object.

Abstract: Methods and systems for encoding data representative of a sequence of video frames for transmission to a decoder. A motion compensated predictive coder (24) substantially losslessly compresses the data, computes a motion vector, and forms an intermediate coded representation which includes the compressed data and the motion vector. A frame detector (26), which detects frames having a prediction error which exceeds a predetermined threshold, is coupled to the motion compensated predictive coder (24). A digital storage device (22) is coupled to the motion compensated predictive coder (24) and the frame detector (26). The digital storage device (22) stores the intermediate coded representation and stores a representation of the frames having the prediction error which exceeds the predetermined threshold. A lossless decoder (29), coupled to the digital storage device (22), substantially losslessly decodes the intermediate coded representation to form a decoded representation.

Abstract: Operating on the principle of vector summation, a predistortion linearizer includes a signal divider on one side of a substrate plate that divides a microwave signal into a linear portion and a nonlinear portion. Signal energy on both the nonlinear and linear portions is coupled into two respective slotline transmission lines on the substrate by uniplanar Magic T hybrids. As the signals are transmitted along the slotlines, their relative amplitudes and phases are adjusted to introduce a distortion inverse to that expected in a subsequent amplification. The linear portion and nonlinear portion pass through another pair of baluns. The signals are then combined by an in-phase summation on the same side of the plate as the input signal divider.

Abstract: A method and system of displaying an image sequence containing a plurality of image frames to inhibit an unauthorized duplication thereof by a camera. The method includes steps of generating a pseudo-random noise sequence, and displaying the image sequence at a frame rate which is varied for successive pairs of the image frames in dependence upon the pseudo-random noise sequence. The frame rate is varied within a predetermined range about a nominal frame rate for the image sequence such that the variations are imperceptible by a human observer. The system includes a pseudo-random sequence generator (30) which generates the pseudo-random noise sequence, and a display device (36) to display the image sequence at a frame rate which is varied in dependence upon the pseudo-random noise sequence.

Abstract: Methods and systems for encoding an audio signal into a bit stream, and for recreating the audio signal from the bit stream are disclosed. In an embodiment of an encoder, a first encoder (10) symbolically encodes a substantially vocal audio signal to form a first encoded signal. A second encoder (12) symbolically encodes a substantially nonvocal audio signal to form a second encoded signal. A multiplexer (14) multiplexes the first encoded signal and the second encoded signal to form the bit stream. In an embodiment of a decoder, a demultiplexer (80) extracts an encoded vocal signal and an encoded nonvocal signal from the bit stream. A first decoder (82) forms a decoded vocal signal based upon the encoded vocal signal. A second decoder (84) forms a decoded nonvocal signal based upon the encoded nonvocal signal. A mixer (86) combines the decoded vocal signal with the decoded nonvocal signal to form the audio signal.

Abstract: A frequency synthesizer having two atomic frequency standard inputs that is adapted to provide seamless switching or transition between the atomic frequency standard inputs with no change in the synthesizer output phase and frequency. The synthesizer includes a multichannel phase comparison system, each channel adapted for handling an atomic frequency standard input, a digital phase lock loop, a digital to analog converter, and a voltage controlled crystal oscillator which provides the synthesizer output. The phase comparison system is adapted to continually monitor the integrity of the atomic frequency standard inputs and to continually estimate the phase differences between the two atomic frequency standard inputs. The phase difference is used to estimate the proper phase and frequency offset between the primary and secondary inputs.

Abstract: A plurality of biphase modulators (42) each modulate a sinusoidal radio frequency signal based upon a corresponding one of a plurality of bits contained in a time-dependent data word. The biphase modulators (42) form a plurality of biphase modulated signals which are communicated to a summing network (40). The summing network (40) contains a plurality of attenuators (44) which attenuate the modulated signals to form a plurality of attenuated signals. The summing network (40) combines the attenuated signals to form a radio frequency signal.

Abstract: A system (12) operative with at least one electromagnetic wave to produce a circularly polarized wave includes a plurality of polarizer sections (56) disposed along a direction of propagation of one electromagnetic wave. The polarizer sections have opposed rows of phase shifting elements, in the form of rods (76), which are adjusted to provide a match to the orthogonal components of the wave. Penetration and spacing of phase shifting elements within each of the polarizing sections attains a match to the two orthogonal components of the wave and a differential phase shift between the two orthogonal components slightly in excess of a desired 90 degree orthogonal phase relationship. Upon a differential counter rotation between a first and a second of the polarizer sections, the total phase shift introduced by the polarizer sections is reduced to 90 degrees without significant shift in the match of the two orthogonal components.

Abstract: A method for stowing a unitary flexible antenna reflector 10 in a confining envelope and deploying the reflector from the envelope. In a most general sense, the invention includes the steps of: a) applying a deforming force to diametrically opposed positions 16 and 18 near an edge of the reflector 10 to place the reflector in a deformed state; b) maintaining the reflector 10 in the deformed state until deployment; and c) releasing the reflector 10 from the deformed state. In a specific embodiment, the step of maintaining the reflector 10 in a deformed state includes the step of attaching a restraining element between the diametrically opposed positions on the edge of the reflector which is released on deployment.

Abstract: A membrane connector or test probe having a group of connector or test probe contacts (14) in a central contact section of the membrane (12) is initially stretched by being axially displaced from the plane of the peripheral membrane support (10). The test probe is cause to contact the pads (43,44) of device (42) to be tested and is then moved through an over travel distance that tends to decrease the amount of the stretch of the membrane. This decrease in stretch effects a small amount of lateral radial displacement of the test probe contacts to provide a scrubbing action that enhances electrical engagement with a circuit chip pad that may have a poorly conductive oxide coating. Substantially all of the stretch of the membrane is caused to be concentrated in and about the central contact section of the membrane at which the test probe contacts are located.

Abstract: A nickel-cadmium cell is activated by means of a formation cycling process in which electrolyte is partially removed and replenished between cycles and the ultimate electrolyte level is controlled by centrifugation following cycling.

Abstract: A semiconductor substrate is etched in a two-step sequence, with two different liquid etchants that have different lateral etch rates. The relative time periods for which the etchants are applied are selected to achieve a close match between the actual etch profile and the desired profile. The process is particularly applicable to the formation of a gate recess in a GaAs MESFET for high power amplification.

Abstract: A pressure-type contact for flexible or conventional wire cable terminations is fabricated from electroformed thin metallic wafers (100) in which one wafer is plated with a raised conductive interconnection feature (122). The electrical circuitry (118, 120) is made on a stainless steel mandrel (10, 10a) having a Teflon pattern (16, 16a) on its surface that allows the desired electrical circuit (30, 32, 34, 30a, 32a, 34a, 78) to be electrolytically plated upon the conductive mandrel surface. The mandrel surface is formed with projecting features in the form of depressions (24, 24a) that will form a series of dots or raised interconnection features on the termination wafers. The mandrel also has projecting posts (76) for providing electrical connection through the substrate.

Abstract: An electrical connector assembly includes two connector blocks that are coupled together by means of a jackscrew on one block that is screwed into a receiver on the other block. The jackscrew and receiver are formed from metal, while the remainder of the connector blocks are formed from a lower cost and lighter weight plastic. The receiver is held in place within a securing member in the second connector block, with the receiver and securing member having complimentary outer and inner polygon surfaces to keep the receiver from rotating. Axial receiver movement is prevented by a boss on the securing member that extends into a recess in the receiver, while the securing member is held against axial movement between a flange on one side and a securing cap on the other.

Abstract: Shaped contacts (40,42) for interconnecting circuits or for use in an integrated circuit test probe are electroplated as integral parts of circuit traces (34) upon a stainless steel mandrel (10). A shaped, hardened steel indentation tool (16,18,26,28) makes indentations (24a,24b) of predetermined shape in the surface of the mandrel (10), which is provided with a pattern of dielectric, such as Teflon (12), or photoresist. Areas of the steel mandrel, including the indentations (24a,24b), are electroplated with a pattern of conductive material (34,36,38), and a dielectric substrate (32) is laminated to the conductive material. The circuit features formed by the indentations define raised contacts of a conical (18) or pyramidal (28) shape, having free ends with a small area that allows higher pressures to be applied to a surface against which the contacts are pressed.

Abstract: A polysilicon gate (42) of an N-channel MOSFET (40) includes a P+ doped central portion (42a), and N+ doped lateral portions (42b,42c) which face an N-type source (24c) and drain (26c) respectively. An N-type dopant is implanted into the surface portion of a P-type channel region (18) to reduce the surface doping and adjust the transistor threshold voltage to approximately 0.8 volts. The lowered channel doping reduces the electric field at the drain (26c) and suppresses injection of hot electrons from the drain (26c) into the gate oxide (14), and also reduces the electric field across the gate oxide (14) and suppresses charging thereof by hot electrons.

Abstract: A rectangular cage formed of near identical grooved support panels (290,292,294,296) slidably mounts horizontal and vertical stacks of circuit boards and circuit board frame assemblies (280,282), with each board of one stack connected to some or all boards of the other stack in edge to edge relation. The cage is open at both front and rear to slidably receive the circuit board frame assemblies that are latched in place by a lever (208) operated cam (210) arrangement on each board frame that engages pairs of latch rods (218) on front and rear edges of the support panels. The support panels are apertured (302,304) to allow air to be blown over the circuit boards and two of the panels (290,292) carry mid-plane terminating panels (342,330) for support of cable connector sockets (38).