Abstract: A combination of frequency and time division multiplexed signals communicates using bursts of higher frequency sinusoidal waves superimposed upon the alternating current in a two-wire power distribution network. A synchronization pattern precedes data, all bursts having the same frequency to overcome problems caused by varying reactances, and all bursts being confined within negative half-cycles of the AC power. Such networks minimize the amount of wire needed to connect large numbers of devices to a common controller while covering large distances, and requiring no particular connection pattern or terminations, whether near the surface, above ground, or in deep earth wells. In an irrigation system they accommodate at once solenoid valves and distributed environmental sensors. Landscape changes that would otherwise require new wiring to accommodate new irrigation zones are facilitated by merely tapping into the two-wire communications lines at the nearest accessible point.

Abstract: Disclosed is a portable navigation and communication system. In one embodiment, the system combines within a single enclosure a GPS satellite-positioning unit, a means of mobile telephony using cell phone technology and a means of personal computing capable of wired or wireless internet/intranet access using a standard operating system. In one aspect of this embodiment, multiple displays can maintain functional independence of simultaneous operations and allow for fail-over to enhance reliability. Further, a speech recognition subsystem can also be included to provide a voice-activated, speech-controlled user interface for hands-free operation.

Abstract: Methods and apparatuses are described for detecting volumetric moisture content and conductivity in various media based on a time-domain reflectometry (TDR) system wherein successive fast transitions are injected into a transmission line immersed in a medium of interest, and a characteristic received waveform is digitized and analyzed by continuously sampling multiple received waveforms at short time intervals. One method transmits a timing signal along a shielded transmission line while a coincident signal is transmitted through the medium of interest. Another method propagates the waveform along a transmission line, that may be either shorted or open-ended, and observes a reflected, rather than transmitted, waveform with a receiver connected to the same end of the transmission line as the transmitter.

Abstract: The invention relates to a wafer transfer system that achieves high efficiency, as measured by throughput rate. This is accomplished in one instance by the combination of reliable transfer of single wafers between ports while being simultaneously rotated to accomplish notch alignment. Another instance allows for simultaneous tilting of a multitude of wafers, such as changing the entire load of a transfer cassette between horizontal and vertical orientations, rather than operating on individual wafers serially. Furthermore, the design of this system renders it usable in both left-handed and right-handed workflow arrangements, not requiring construction of mirror-image systems and thereby achieving an economy of scale in production and inventory of the wafer transfer system itself.

Abstract: A method of sensing moisture based on propagation-delay provides absolute readings of volumetric water content in a moisture-bearing medium without calibrating the sensor or its readings for the conductivity or temperature of the medium. A fast transition is launched on a transmission line that is immersed in the medium to be measured. The amplitude of the resultant waveform is analyzed at precise, programmable time increments by using a high-speed latching comparator. Firmware in a controlling microprocessor facilitates the successive reconstruction of the significant characteristics of the returning waveform. The microprocessor analyzes these characteristics to provide an accurate determination of propagation delay and conductivity, even for severely distorted waveforms. The moisture content of the medium is derived from the propagation delay.