Abstract: A method for optimal track assignment in a grid-based channel router. Initially, interconnection information is extracted from a global routing result. Multiple pin nets derived from the interconnection information are decomposed into simpler mapped segments. A channel grid map is then built and marked with existing objects. Next, a vertical constraint graph specifying the relative positions of the mapped segments is constructed. A first track is computed. A track assignment loop is repeated until all requisite connections are realized. The track assignment loop includes the steps of breaking cycles and long paths and collecting a set of feasible links. One or more weighting functions are assigned to each such feasible link. A dynamic programming approach is used to select an optimal set of feasible links according to the weighting functions. In addition, an optimal set of feasible links corresponding to unpreferred layers is collected by applying dynamic programming.

Abstract: A GPS antenna comprises an antenna body that can rotate between horizontal and vertical positions between the handle horns on the top of an optical total station. A GPS receiver embodiment comprises an integrated body and antenna that can similarly be rotated between horizontal and vertical positions between the handle horns on the top of an optical total station to avoid interference with the total station optics.

Abstract: A direct sequence spread spectrum (DSSS) radio communication system of the present invention comprises a transmitter and a matching receiver. The transmitter includes a pseudorandom number (PRN) code generator, a chip clock generator and a 16.times. clock generator that runs at sixteen times the chip clock rate. The output of the PRN code generator and chip clock generator are exclusive-OR'ed to derive a Manchester encoding of the DSSS spreading code. A tri-state buffer is used to deliver such Manchester encoded DSSS spreading code to a mixer to spread a biphase shift keyed (BPSK) radio carrier before being transmitted. The tri-state buffer can be a part of the exclusive-OR logic and is connected to place its output in a high impedance state one sixteenth of every chip clock period. This provides for a suppression of the spurious sidebands that otherwise limit adjacent channel packing.

Abstract: A short-coupled-path extender comprises a two-inch thick housing that inserts as a spacer between a plasma source and a vacuum chamber in various kinds of semiconductor processing equipment. The spacer housing is generally constructed of aluminum and is thermally well-connected to the vacuum chamber and its liquid cooling system to dispose of the heat it collects from the plasma source flow. The plasma source bolts up to a central inlet port on the spacer housing that leads to a first quartz-lined antechamber within. The plasma source flow encounters a traverse metal wall at the back of the first antechamber and is forced to flow radially outward to a system of small outer ports that connect to a second quartz-lined antechamber. The plasma source flow then collects back together and exits the second antechamber through a central outlet port that bolts up to the plasma source seat on the vacuum chamber.

Abstract: In a GPS navigation satellite receiver, a pseudorange step detection method integrates the pseudorange rates to predict expected changes in the pseudoranges from one measurement to the next. The pseudorange rate is directly measured as the carrier Doppler shift. The pseudorange and pseudorange rate from a last measurement from each satellite and a pseudorange rate from a new measurement are used to estimate the expected pseudorange. Such estimate accounts for vehicle velocity and accelerations. The expected pseudorange is compared to a newly measured pseudorange. An impermissible pseudorange step is declared when the difference exceeds a variable threshold. Tests can be done on measurements taken up to ten seconds apart, e.g., using a threshold of five hundred meters. The maximum position dilution of precision is typically set at a value of twelve. Satellites that manifest a pseudorange step are thereafter excluded from participating in subsequent position solution activity.

Abstract: A video cassette recorder includes a tape transport and servo that records digital data at one tape speed and plays back the digital data at one twentieth of the recording speed, both with a fixed speed of rotation of a drum head. On playback, each recorded segment of data on the tape is read from ten slightly different longitudinal positions on the magnetic tape, with the highest amplitude read-back signal being selected. The drum head comprises two playback heads that each have playback widths that are approximately twice as wide as each of four recording heads in the drum head.

Abstract: Hierarchical look-ahead congestion-driven placement is a look-ahead method for avoiding interconnect congestion. It balances the available routing resources. When incorporated into conventional quadratic programming approaches, only minor increases in run-time are needed to produce dramatic decreases in congestion. The macrocell densities are traded between adjacent regions to anticipate congestion, and are estimated based on the current iteration for the distribution of cells and net connections involved. The congestion estimation also takes routing detour due to the presence of large hard macros into account for accuracy. The macrocell density adjustments are propagated to all the neighboring regions at each hierarchical level to revise the prior congestion estimate from the previous hierarchical iteration.

Abstract: A system and method for immediately separating oil sands into three layers uses a logwasher with paddles that mixes the oil sands with hot water and steam. The three layers of bitumen, clay/sand/water slurry and rock separate effectively and immediately and are not re-mixed in further processing as was conventional, further producing a clay fraction from the fines for mineral processing.

Abstract: In a grid-based channel router, a method for handling variable width wires. The user initially specifies the widths of the wires. In this manner, wider wires may be selected for special nets, such as those used for routing clock signals, whereas narrower wires are used for normal nets in order to minimize the die size. A refined grid map is generated. This refined grid map consists of extra rows and columns for marking the variable width wires. These extra rows and columns are spaced as a function of the wire width and are marked the same as with normal rows and columns. Before a wire is placed, the affected rows or columns are checked for any violations. If there are no violations, the wire is placed and the appropriate rows or columns are marked. Due to the extra rows and columns, the problems associated with overmarking and undermarking variable width wires are avoided.

Abstract: A non-contact pneumatic-electric dimensional measurement system comprises a stable base on which a semiconductor wafer or workpiece to be measured is placed. A measurement head is held aloft over the wafer or workpiece and base by a rigid support bracket attached to the base. The tip of an air nozzle in the measurement head is directed at the wafer or workpiece and automatically extended to near contact. The nozzle is servo-positioned by an air sensor and motor combination that maintains an air gap between the tip and wafer of about 150 microns with an overall precision of about 3-4 microns. A Heidenhaim linear displacement gauge is attached to the air nozzle and is used to determine the nozzle position to within 0.5 micron. The dimension of the wafer or workpiece is determined to within 0.5 micron by combining the linear displacement gauge reading with an estimate of the air gap derived from a reading of the air nozzle backpressure that has an accuracy of about 0.1 micron.

Abstract: A process in which a leach liquor of Al.sub.2 (SO.sub.4).sub.3 +K.sub.2 SO.sub.4 +Fe.sub.2 SO.sub.4 and other sulphates is introduced to a surface-cooled crystallizer that drops the Al.sub.2 (SO.sub.4).sub.3 +18H.sub.2 O. The leach liquor is pumped through a heat exchanger that keeps a temperature of 160.degree. F. and the surface temperature of the surface-cooled crystallizer is maintained at 60.degree. F. The temperature gradient within the leach liquor promotes crystal formation. These crystals are then supplied to mixture which includes K.sub.2 SO.sub.4 in a simple crystallization and evaporation step that uses a vacuum of twenty inches of mercury and heat to drop Al.sub.2 (SO.sub.4).sub.3 +K.sub.2 SO.sub.4 +24H.sub.2 O. A pressure of 250 PSI and a temperature of 200.degree. C. are then applied in a discrete continuous process that yield a basic sodium or potassium aluminum sulphate and excess sodium sulphate or potassium.

Abstract: An insulation material comprising the double salt of aluminum potassium sulphate and method of producing such. Aluminum sulphate materials and potassium sulphate materials are combined to form aluminum potassium sulphate which is then dehydrated to remove the water of hydration. Porous forms are made by mixing the hydrated aluminum potassium sulphate with a binder before dehydration. The resultant dehydrated sulphate expands greatly to provide an insulative material which is of lightweight and inorganic.

Abstract: An initialization method comprises loading a real time kinematic GPS base receiver with at least one position benchmark and setting a snap mode on and selecting a snap distance. The base receiver is transported to the earth location corresponding to any one of the position benchmarks. The base receiver is turned on. The base receiver estimates its rough position in a way that allows for a quick initial solution. If such rough estimate solution is within the snap distance of any one position benchmark, then the initialization of the base station is forced to assume the position benchmark is the present position, e.g., to sub-centimeter level accuracy.

Abstract: A single-chip video compression/decompression (video codec) chip is connected to receive a video input from a NTSC-compatible or PAL-compatible camera and a transmit channel. Video information from the camera or other video input source is compressed by the video codec and transmitted out in compressed form on a transmit channel. Concurrently, compressed video information is input to the video codec from a receive channel, decompressed and output to the monitor or other video output device, e.g., a television set. Only a separate single module of dynamic random access memory (DRAM) is needed to provide storage for incoming and outgoing video data, compressed bit streams and reconstructed pictures for both compression and decompression procedures. The compression of video information is by spatial decorrelation of the intraframe information, and temporal decorrelation of the interframe information. The communication channel bit rate is further reduced by quantization and variable length coding.

Abstract: A weep drain for a tile wall includes a dam for collecting water, moisture, or other liquids and an extrusion with a plurality of hollow cylindrical tubes for allowing the water, moisture or other liquids to drain from behind the tile wall.

Abstract: For use in explosive atmospheres during mining, an flame proof or explosion proof internal AC alternator is provided to source electrical power from the rotations of a cutting head. A synthetic-pulse stepped-frequency ground-penetrating radar is used with oppositely circularly polarized transmitting and receiving antennas in a phase coherent microwave transceiver to measure the thickness of a coal deposit and to control the cut of a continuous mining machine operating in an underground mine. For example, a stepped-frequency radar and resonant microstrip patch antennas mounted near the outside surface of the cutting head to obtain measurements.

Abstract: A system and method for immediately separating oil sands into three layers uses a logwasher with paddles that mixes the oil sands with hot water and steam. The three layers of bitumen, clay/sand/water slurry and rock separate effectively and immediately and are not re-mixed in further processing as was conventional, further producing a clay fraction from the fines for mineral processing.

Abstract: A surveying instrument comprises a tripod with a tribrach that receives both a theodolite and a C-bracket that half vertically encircles the theodolite. The C-bracket and the theodolite are each independently pivotable on the same vertical axis and the C-bracket is able to completely orbit around the theodolite such that it can be positioned so as not to optically interfere with the use of the theodolite. The top of the C-bracket provides a mount for a navigation satellite receiver antenna that positions the axis of rotation of the C-bracket through the electrical center of the antenna.

Abstract: A memory system comprises an array of parallel removable hard disk cartridges and matching drives. Each cartridge is recorded with an array position signature so that an array can be programmatically reconstructed each time the cartridges are loaded in their drives without regard to the original physical associations of cartridges to drives.

Abstract: A method comprises receiving a diskette into a drive, determining the logical format type of the data written on the diskette, and targeting any recorded track on either surface of the diskette that has both inner and outer adjacent tracks. The head actuator in the drive is moved to the expected position for the targeted track that has been determined by a factory precalibration. The head actuator is then stepped inside by one sixteenth of the width of a standard track pitch and an attempt is made to read a sector header from the recorded track. If the reading of the sector header succeeded, the head actuator is stepped in again by one sixteenth and the sector header is read again. Such inward stepping is continued until the reading of the sector header fails. The radial position at which this occurs is defined as the inner boundary of the track. The outer boundary is found in similar fashion. The track center is computed as the midpoint between such inner and outer boundaries.