Abstract: A method of building systematically a multi-dimensional (n, D, L) circular trellis coded modulation (CTCM) encoder with properties of optimal energy efficiency, strong tail biting and maximum minimum distance (dmin) of trellis paths is disclosed.

Abstract: A precisely sized transparent cardholder for two fare zone commuters that use both bus pass and magnetic strip subway card simplified into one cardholder. The use of a Poly Vinyl Chloride with 0.13 mm thickness makes this design possible and to properly form the two pockets into one cardholder. The transparent cardholder consist of three transparent panels: (i) front panel, (ii) inner dividing panel, and (iii) the back panel. The front panel is sealed to the inner dividing panel from the left side, right side and the bottom as to form the larger pocket for the insertion of the bus pass. The back panel is sealed ¾″ up from the bottom to the inner dividing panel and sealed from the left side and right side as to form the smaller pocket for the insertion of the magnetic strip subway card. The smaller pocket is specifically designed that plastic does not overlap the magnetic strip. The opening for both the larger pocket and the smaller pocket on the top are equally leveled and sized.

Abstract: A source of interference signals may be present at a fixed incident angle relative to a stationary antenna. Horizontal array antennas are provided with radiation pattern notches or nulls at selected fixed angles to suppress reception of interference signals. By excitation of elements on the left side of an array in opposite phase relative to elements on the right side and provision of an appropriate line-length differential between left and right radiation element feed lines, a radiation pattern notch is positioned at a selectable angle relative to boresight. Notch width optimization is provided by use of relative excitation levels of radiating elements as disclosed. Other configurations are disclosed.

Abstract: A corner insert for edge strips used with modified electrodes for electrolytic processes. An electrode that is at least partially submerged in an electrolyte is protected by edge strips to prevent depositions and metallic bridges. The edge strips are typically mitered to abut one another at the corners of the electrode and it is difficult to seal this junction. One solution is to remove the corners of the electrode, provide non-mitered edge strips, and close the gap at the corner with an insert adapted to seal to the additional edges of the electrode created by removing the corners. Another solution is to provide a corner insert having one or more anchors for anchoring the corner insert to the electrode and to respective adjacent edge strips, the corner insert sealing against the edge strips and against opposite sides of the electrode whether or not the corner portion has been removed.

Abstract: This invention is a method for creating systems that support visual editing and manipulation of arbitrary (any language) textual source code as graphical flowcharts. The cornerstone of this invention is a textual Flow Structure Markup Language (FSML) that encodes algorithmic flow information representing the logical procedural intent of a file (or files) of textual code. The FSML can be placed within a file containing both text source code and FSML encoded flow information, or in parallel as a secondary file that stores the flow information, or as an attribute in a database record wherein each record can also contain a single procedural instruction of the procedural language or reference therein. In all embodiments the flow information is synchronized with the text code instructions so that each line, or instruction of text code, has a corresponding line, tag, or identifying mark that denotes, or encodes, the type of flow that a text code instruction represents.

Abstract: For broadcast transmission of Differential GPS data signals, a vertical array antenna provides broad band omnidirective phase-progressive radiation with elliptical polarization. Four-dipole sub-arrays use diagonally aligned two-piece cut and bend dipoles with isolated conductive frontal strip. With these vertically arrayed sub-arrays, lower and upper sub-arrays are excited at 70 percent amplitude and respective plus and minus 90 degree phase rotation relative to middle sub-array, for optimized performance with low elevation lobing. Divided transmission line operation provided by the frontal strip of appropriate length achieves double-tuned dipole performance with very low VSWR over the operating band.

Abstract: A dual-radiator whip antenna to operate over a 30 to 450 MHz frequency band includes a high frequency dipole above a low frequency monopole. The outer conductor (30) of a coaxial line is configured to operate as a monopole. Above the upper terminus of the outer conductor, an extension (32a) of the inner conductor (32) is configured as the upper arm of a dipole. An upper length of the outer conductor also functions as the lower dipole arm. With a single antenna port (13), a diplexer and other feed elements separate signals into high and low frequency bands respectively coupled to the dipole and monopole radiators. Increased high frequency range results from positioning of the center of radiation of the dipole above the monopole.

Abstract: A self-contained four-dipole element provides a 360 degree phase-progressive-omnidirectional (PPO) circularly polarized antenna pattern. Via a single signal port, a PPO excitation network incorporated into the element excites the four dipoles at phases differing by successive 90 degree increments. The four-dipole element is adapted for efficiently reproducible fabrication using printed circuit techniques. Antennas employing a stack of the elements provide a hemispherical antenna pattern with PPO circular polarization and a sharp cutoff below horizontal. For GPS reception in Differential GPS aircraft landing applications, a 21 element antenna provides multipath suppression and a unitary phase center enabling avoidance of signal phase discrepancies. More or fewer elements may be employed in other applications.

Abstract: Low impedance loop antennas utilize a loop separated into a plurality of radiating segments fed in parallel. A four point feed loop antenna, including radiating segments 12, 13, 14, 15 had a measured input impedance varying from 1.8 to 5.8 Ohms over a range of 5 to 15 MHz, without excessive radiation Q degradation. An incorporated feed network includes transmission line segments, with conductors on opposite surfaces of a thin substrate, connecting the radiating segments to a centrally mounted coaxial connector for parallel excitation. Operating bandwidth of the loop antenna is determined by the characteristic impedance of the transmission line feed segments. Low impedance loop antennas which are small relative to operating wavelength can be fabricated on a thin flexible substrate for field transport and use. Incorporation of the antenna into a jacket or other clothing enables field use while minimizing restriction of activity of the user.

Abstract: Omnidirectional cellular coverage may be provided by installing four 90 degree antennas on the sides of a tower. However, in a prior system pattern uniformity will be destroyed by nulling effects if the tower width causes the lateral separation between adjacent antennas to be large. Nulling effects in areas of overlap between beams of adjacent antennas are avoided by providing an omnidirectional pattern characterized by signal polarization which changes with azimuth. Cross polarization of adjacent antennas is achieved by providing North and South antennas with +45 degrees linear polarization and East and West antennas with -45 degrees linear polarization (alternating antennas with right and left circular polarizations may also be used). Portable cellular receivers for use with the antenna system may typically utilize antennas with either vertical or horizontal linear polarization.

Abstract: Double-tuned radiating elements 10 for cellular antennas are configured to enable stamping in one piece from flat sheet metal. Unitary construction incorporates a radiating section 22, an exciter section 14 and a balun section 12 in each radiating element. After the element is formed in one flat piece, a 90 degree bend is made along bend line BL to position radiating section 22 normal to the exciter and balun sections. When mounted in an antenna with the exciter and balun sections 14 and 12 parallel to a conductive ground plane surface, radiating section 22 extends forward normal to the ground plane surface. Radiating section 22 and exciter section 14 are fed by direct coupling to balun section 12, via shared current paths.

Abstract: Cellular antenna systems are provided for airship-type support at a position in the stratosphere. A single antenna system (20) may provide cellular communication for earth-based users located anywhere within a circle 400 miles in diameter (10). By use of array assemblies (21a) each providing 12 side-by-side beam positions per quadrant, with higher and lower elevation beams (32a', 36a') at each beam position, coverage can be provided for 96 cells arranged side-by-side in inner and outer annular bands (10). A turnstile-type antenna (26) provides coverage for a 97th central circular cell. By allocation of available groups of cellular frequencies in repetitive patterns around the outer annular band (1-6, FIG. 1), with frequency reuse in offset positions around the inner annular band, 16 times frequency reuse is provided while maintaining acceptable co-channel interference levels.

Abstract: U-dipole radiating elements (10) and associated feed conductors (20, 22) are cut or stamped from brass sheet stock. Each U-dipole (10) is then bent up at 90 degrees to the signal distribution conductor (22) which is supported in front of a reflector (12). The U-dipole element (10) includes a first dipole-type conductor segment (14) connected near one end to a feed segment (20) which is the sole signal feed path to the U-dipole element. A second dipole-type conductor segment (16), which is spaced from and parallel to and coextensive with first segment (14), is connected to the other end of the first segment (14). An antenna may include one or more individual U-dipole elements cut from sheet stock and connected to feed points. In a linear array antenna configuration, a group of U-dipole elements (10a-10b) and associated signal feed network components may be cut in a unitary form from a sheet of conductive material and supported in front of a reflector surface.

Abstract: In a cellular type communication system a sector antenna 12 provides coverage of a sector with a relatively low receive gain. A multi-beam antenna 20 covers the same sector with a plurality of narrower beams 21', 22', 23' and 24' providing higher gain. A multi-beam antenna system 10 provides higher gain operation by selecting the one of the narrower beams 21', 22', 23' or 24' currently providing best reception of a signal transmitted by a user and coupling that selected beam to a system receiver 18. Beam selection is accomplished by sequentially coupling each narrow beam to a microprocessor based control unit 40 and storing samples of user signals as received in each narrow beam on a continuing repetitive basis. The stored samples are then analyzed in order to select the beam currently providing best reception.

Abstract: Performance of multibeam cellular antenna systems is improved by use of space diversity in antenna placement and angle diversity in antenna alignment. Space/angle diversity is achieved on a single tower structure (20) by placement of eight antennas (B1-B8) in pairs at four spaced locations (I, II, III, IV) at the tower corners. Antennas are placed with an orthogonally directed pair at each location. For each orthogonal pair (e.g., B1 and B2 at location I) there is an antenna located at a different corner which is pointed between the orthogonal directions (e.g., B5 at location II). Antenna placement and alignment for achieving space/angle diversity in triangular tower configurations are also described.

Abstract: Multi-beam antenna feed networks employ more aperture ports (e.g., ports I, II, III, IV and V) than beam ports (e.g., ports A, B, C and D) to achieve low sidelobe lossless operation, particularly for cellular communications. With five aperture ports, signal value outputs at the aperture ports represent orthogonal outputs having phase gradients effective to provide a four beam radiation pattern. The feed arrangement includes directional couplers (e.g., C11, C21) and phase shifters (e.g., P22, P23) intercoupled between the beam ports and aperture ports to provide the desired orthogonal aperture excitation. An example of specific directional coupler and phase shifter circuit values for a matrix network for a four beam port to five aperture port feed network configuration is provided.

Abstract: A heat exchanger comprises a cooling frame including first and second frame portions that releasably engage fin material. In one embodiment of the heat exchanger, first and second frame portions are movable with respect to each other. A fin module, which can include fragile or pliant fin material secured to a more robust strip of material, is positionable between the first and second frame portions. A tension device, such as a spring or a spacing controller, urges the frame portions together to bind the fin module between the frame portions. Releasing tension or urging the frame portions in an opposite direction releases the fin module. The fin module can also be retained within the cooling frame with one or more clips.

Abstract: In a cellular type communication system a sector antenna 12 provides coverage of a sector with a relatively low receive gain. A multi-beam antenna 20 covers the same sector with a plurality of narrower beams 21', 22', 23' and 24' providing higher gain. A multi-beam antenna system 10 provides higher gain operation by selecting the one of the narrower beams 21', 22', 23' or 24' currently providing best reception of a signal transmitted by a user and coupling that selected beam to a system receiver 18. Beam selection is accomplished by sequentially coupling each narrow beam to a microprocessor based control unit 40 and storing samples of user signals as received in each narrow beam on a continuing repetitive basis. The stored samples are then analyzed in order to select the beam currently providing best reception.