Abstract: An array ultrasonic transducer precursor includes a body of piezoelectric material with a dielectric substrate bonded to a surface of the body. Circuit elements supported on the dielectric substrate include, in an active region, physically parallel signal conductors arranged in a pattern with spaces between adjacent ones of the conductors. Dicing saw cuts made in these spaces define individual circuit elements within the piezoelectric body. The circuit elements outside the active region include a set of resistive alignment elements in predetermined positions with reference to the pattern of signal conductors. The transducer precursor is mounted in a dicing saw fixture, and initial cuts made with the dicing saw remove portions of the resistive alignment elements. Locations of the initial cuts with reference to the resistive alignment elements are determined by measuring resistances of the resistive alignment elements after the initial cuts.

Abstract: A direct sequence spread spectrum signal processing system permits the receiver to be turned off during most of the acquisition phase of reception to significantly reduce the on time of the associated receiver front end. Power requirements are further reduced by use of very low power high accuracy time and frequency circuits in GPS based tracking units. The microprocessor based GPS tracking system is shut down almost all the time, using extremely little electrical power, and is powered up for very short periods of time at scheduled intervals by an extremely low power clock circuit with accuracy that varies with temperature. Each time the microprocessor is powered up, system temperature is recorded in memory. At times when the microprocessor is powered up, the GPS system is accessed and the GPS standard time is read. The difference between the low power clock circuit based time and the GPS based time is correlated with the recorded temperature history.

Abstract: A system for communicating digital information over wires having a great deal of harmonic distortion, such as a power line, employs a transmitter which transmitter which creates a carrier wave for each of a plurality of signals to be sent. This carrier wave has frequency lobes positioned between the frequency lobes of the harmonic distortion. Each of the lobes of a single carrier signal is encoded with the same bit value during a given bit period. This signal is then mixed with any existing signal on the wire. At a remote receiver coupled to the wires, the signal is sensed, filtered, and Fourier transformed into coefficients. The signal-to-noise (S/N) ratio of each Fourier coefficient is determined by a novel S/N estimation technique. The coefficients are weighted based upon the S/N ratio estimation, and decoded, preferably by an inner product of the weighted Fourier coefficients. Additionally, the S/N ratio estimates could be time averaged before being used in the weighting and bit decoding.

Abstract: A junction box architecture includes a main circuit breaker, plurality of branch circuit breakers, and an arc detection unit. The main circuit breaker input is connected to main power supply lines, e.g., phase 1 and phase 2 power lines. The main circuit breaker output is connected to respective inputs of branch circuit breakers and to an input of the arc detection unit. The arc detection unit includes an enable output and is configured to generate an enable signal on the enable output. The enable output is coupled to enable inputs of each branch circuit breaker. When no enable signal is present on an enable input of any one branch circuit breaker, the one breaker will not trip. In general, for any one circuit breaker to trip, the breaker must simultaneously detect a high frequency current in the associated branch circuit and receive an enable signal from the arc detection unit.

Abstract: A pressure sensor having structure for generating a magnetic force to balance forces on opposing sides of a flexible diaphragm centered within a pressure chamber allows fluid pressure to be introduced into the chamber on one side of the diaphragm. A first magnetic coil is positioned on another side of the diaphragm and a second coil is mounted to the diaphragm. When fluid pressure is introduced into the pressure chamber, the diaphragm deflects, and the magnitude of current required to generate a recentering magnetic force which causes the diaphragm to be recentered constitutes a measure of the fluid pressure. Since the recentering magnetic force is substantially unaffected by temperature, the fluid pressure measurement obtained is substantially independent of temperature.

Abstract: A redundant sensor system for predicting railway hazards including breaks in each rail, the location of the breaks, and determining when a railway vehicle has a flat wheel. Vibration sensors are distributed along both rails of a railway. Each sensor has a detection band at least within the sensing range of adjacent sensors and it is positioned such that the sensor detects vibration in both the horizontal and vertical axis of the rail. A central processor evaluates the data from these sensors and identifies the rail break, the location of the break, and the flat wheel.

Abstract: An array ultrasonic transducer precursor includes a body of piezoelectric material with a dielectric substrate bonded to a surface of the body. Circuit elements supported on the dielectric substrate include, in an active region, physically parallel signal conductors arranged in a pattern with spaces between adjacent ones of the conductors. Dicing saw cuts made in these spaces define individual circuit elements within the piezoelectric body. The circuit elements outside the active region include a set of resistive alignment elements in predetermined positions with reference to the pattern of signal conductors. The transducer precursor is mounted in a dicing saw fixture, and initial cuts made with the dicing saw remove portions of the resistive alignment elements. Locations of the initial cuts with reference to the resistive alignment elements are determined by measuring resistances of the resistive alignment elements after the initial cuts.

Abstract: A mobile local area network (LAN) of tracked assets utilizing minimal power and bandwidth allows a large number of assets to be tracked in a practical manner. The mobile LAN is established between a plurality of tracking units in close proximity. Assets are approximately located according to their connection in the mobile LAN where the exact location of at least one of the network nodes is known. Each tracked asset has capability to independently determine and report its position to a central station, and each asset also has capability to communicate locally with other cooperative assets via the LAN. The LAN is dynamically reconfigurable so that as other cooperative assets come into proximity, they can join the network, and as others move away, they can leave the network. Within the network, a protocol is followed which assigns one of the assets to be the "master" and all others to be "slaves".

Abstract: The condition and/or integrity of goods is monitored while in transit using a local area network of tracked assets. Autonomous electronic sensors are situated in proximity to the cargo being shipped. These sensors communicate with an asset tracking unit affixed to the container for the goods via a mutter mode transceiver. The tracking unit has the ability to relay the cargo sensor data to the central station on demand, on exception, or on a predetermined schedule established by the central station. Communication between the cargo sensors and the tracking unit may be one-way (i.e., sensor to tracking unit) or two-way. Multiple sensors may communicate with each tracking unit.