Abstract: Spread spectrum transceivers communicate using code sequences having low cross-correlations and well-peaked autocorrelations. The initial communications involve broadcasting a beacon signal consisting of a beacon packet repeated at regular intervals (the cycle time). The code sequences may be period-(2n−1) Small Kasami sequences; the beacon packet is a repeated series of (2n/2+1) period-(2n/2−1) progenitor maximal sequences, and behaves like a member of the Kasami family. The acyclic autocorrelation of the beacon packet has regularly-spaced sharp peaks modulated by a pyramidal envelope. The initial communications involve calculating the correlation between the received signal and delayed versions of an internally-generated beacon packet. The length of the initial communications is proportional to the square of the cycle time divided by the width of the acyclic autocorrelation.

Abstract: An ultra-wideband, large-current radiator consisting of a ground plane and two electric monopoles: a wide radiating monopole orthogonal to the ground plane, and a thin monopole orthogonal to the ground plane and normally displaced from the wide monopole. The frequency-independent low impedance of the antenna allows a small voltage to generate a large current. The wide radiating monopole may be a flat sheet, or a sheet of parallel bars. Shielding by the wide monopole suppresses radiation from the thin monopole into a sector of space into which the monopole radiation characteristic of a well-formed impulse in response to a voltage step is desired. In one preferred embodiment, two parallel flat sheets or a conducting cylinder is used as the wide radiating monopole, further shielding radiation from the thin monopole.

Abstract: A bipedal locomotion exercise and performance evaluation apparatus including a revolving belt, a harness for securing the position of a subject on the belt, a harness-force measuring means, and a belt volocity monitoring and controlling means. The harness may be secured on various points of a subject and includes push/pull engagement means. An overhead harness may be used to reduce effective body mass. The velocity of the belt may be controlled by a unidirectional or bidirectional motor/brake system. Velocity of the belt may also be controlled by a brake only. A digital processor may be used to control the motor and/or brake as a function of the forces applied allowing multiple operating modes. Recording of velocity and force as functions of time facilitates analysis of exercise performance. The apparatus allows exertions throughout the first quadrant of a force-velocity-duration space, and outside that first quadrant.

Abstract: A network of localizers determines relative locations in three-dimensional space to within 1 cm by measuring propagation times of pseudorandom sequences of electromagnetic impulses. The propagation time is determined from a correlator which provides an analog pseudo-autocorrelation function sampled at discrete time bins. The correlator has a number of integrators, each integrator providing a signal proportional to the time integral of the product of the expected pulse sequence delayed by one of the discrete time bins, and the non-delayed received antenna signal. Using pattern recognition the arrival time of the received signal can be determined to within a time much smaller than the separation between bins. Because operation of standard CMOS circuitry generates noise over a large frequency range, only low-noise circuitry operates during transmission and reception. A stage in the low-frequency clock uses low-noise circuitry during transmissions and receptions, and standard circuitry at other times.

Abstract: A network of localizers determines relative locations in three-dimensional space to within 1 cm by cooperatively measuring propagation times of pseudorandom sequences of electromagnetic impulses. Ranging transmissions may include encoded digital information to increase accuracy. The propagation time is determined from a correlator circuit which provides an analog pseudo-autocorrelation function sampled at discrete time bins. The correlator has a number of integrators, each integrator providing a signal proportional to the time integral of the product of the expected pulse sequence delayed by one of the discrete time bins, and the non-delayed received antenna signal. With the impulses organized as doublets the sampled correlator output can vary considerably in shape depending on where the autocorrelation function peak falls in relation to the nearest bin. Using pattern recognition the time of arrival of the received signal can be determined to within a time much smaller than the separation between bins.

Abstract: A room-environment string-pull construction toy consisting of a string, multiple wall-mountable pulleys, and a variety of colorful, eye-catching and/or whimsical cardboard or paper cutouts which can be mounted on the pulley wheels. Each wall-mountable pulley has a base with a non-permanent adhesive affixed to a back surface thereof, and an axle extending from a front surface thereof on which a pulley wheel is rotatably mounted. The configuration of the toy is constructed by attaching the pulleys to the walls and possibly the ceiling of a room, running the string over the pulleys, and attaching cutouts to the pulleys and string. Planar cutouts attached to the pulley wheels may be shaped as propellers, arrows, cams, disks and the like. Preferably, the cutouts are bright colors and/or are decorated with designs which have a striking appearance when in motion.

Abstract: Method and apparatus for increased accuracy of an image of object density pixel values obtained by forming linear combinations thereof. A measured variable M is related to an integration of the actual object density .rho. over space q by a transform function F, i.e., M(t)=.intg.F(t, q).rho.(q)dq, and an estimated object density .rho.* is obtained by an approximate inversion of the transform function, i.e., .rho.*(q)=.SIGMA.E(t,q)M(t), where the sum is over the samples taken. (In the case of magnetic resonance imaging, M is the magnetization induced in a coil transverse to the main magnetization coil, the transform function F(t,q) includes sinusoidal components, and the inversion function G includes an inverse Fourier transform.) Therefore, the estimated object density .rho.* is related to the actual object density .rho. by.rho.*(q)=.intg..SIGMA.E(t,q)F(t,q').rho.(q')dq',and .SIGMA.E(t,q)F(t,q') is termed the kernel A(q,q').

Abstract: A marble track construction toy for assembly on a vertically-oriented planar surface. The construction toy includes chutes down which the marble can roll, pivot elements and bumpers for altering the direction of the motion of the marble, and a catch basket for retaining the marble at the terminus of the track. Each chute includes a mounting means so the chute can be mounted on the vertically-oriented planar surface with both ends of the chute oriented parallel to the planar surface. Similarly, each bumper includes a mounting means so the bumper can be mounted on the vertically-oriented planar surface with an impact surface oriented perpendicular to the mounting surface. And each pivot element has a bucket and a pivoting bucket arm, and includes a mounting means so the pivot element can be mounted on the vertically-oriented planar surface such that the bucket pivots in the plane of the mounting surface.

Abstract: A constructable spinning top maze kit having a base upon which rail pieces may be removably mounted to form a maze through which the spinning top may travel when launched from a launcher. Multiple bases may be joined together in a single plane to create an indefinitely-extendable maze, or multiple bases may be assembled in multiple planes to create an indefinitely-extendable multi-level maze. Because rail pieces are removably mounted on the base pieces, a maze may be disassembled and reconstructed to form another maze have a completely different geometry, or one or more rail pieces may be repositioned to less drastically alter the geometry of the maze. As with the rail pieces, the launcher may be removably mounted on the base pieces. Therefore, the launcher may be positioned at a variety of locations in a maze, easily repositioned, and used within a variety of maze geometries.

Abstract: A marble track is constructed from cubes, base blocks, tower dowels, track dowels and rubber bands. Each cube has four vertically oriented tower bores, through-bores of approximately the width of the tower dowels, adjacent and parallel to the four vertical edges of the cube. Each base block has four vertically oriented tower bores with the same spacing as the tower bores in the cube. Cubes may be positioned on tower dowels extending vertically from a base block, and the position of a cube may be stabilized by a rubber band around the tower dowels just below the cube. A channel in each cube (except the "end cubes") permits a marble to pass through the cube. A channel may be bifurcated, and may have entrances/exits to any combination of the six faces of a cube. Track dowels may be inserted in track bores below each side channel entrance/exit to permit the marble to roll out of the channel and onto the track dowels.

Abstract: A cylindrical metal disc is optimized to spin/roll on a base for an extended length of time, and as the angle of inclination of the disc decreases to zero, a tone emitted by the spinning/rolling of the disc rises in pitch towards infinity. To optimize the spinning/rolling time, the radius-to-height aspect ratio of the disc is approximately three, the upper surface of the base and the lower edge of the disc are smooth and hard to enable the disc to spin/roll for an extended length of time, and the base has three legs and is solidly constructed to minimize energy losses due to vibration. The upper surface of the base is concave to prevent the disc from wandering as it spins/rolls. The top of the disc is tessellated with tiles having effectively random optic orientations to produce the appearance of a cloud of sparkling lights in the vicinity of the top surface of the disc as it spins/rolls.

Abstract: A set of three-dimensional construction elements which removably adhere to one another for use as a construction toy or as a decorative display structure. Surfaces of the elements are substantially covered with hook-and-loop fastener material in accordance with "surfacing patterns" which maximize inter-connection flexibility. The "3-point" surfacing pattern for rectangular prisms, and derivatives of the 3-point pattern for other shapes, provide a unified surfacing system which promotes ease of use. Derivative 3-point patterns may be determined by morphological transformations of a rectangular prism with a 3-point surfacing pattern. The 3-point pattern and its derivatives obey a set of surfacing guidelines which maximizes the number of ways of forming face-to-face, edge-to-face, and point-to-face connections.

Abstract: A complete bubble blowing assembly which can be worn as a necklace. A small bubble horn capable of producing large bubbles is attached as an ornament to a necklace cord. A vial for containing bubble solution may be removably attached to the horn for transportation. During bubble blowing play the vial is separated from the horn so that the horn can be dipped into the bubble solution, priming the horn for bubble blowing. The lid of the vial can be attached to the bottom of the vial providing a stable base for the vial and preventing loss of the lid during play.