Abstract: The present invention is an isothermal current shunt device with excellent temperature coefficient of resistivity characteristics stability for use in a power measuring circuit having a wide temperature and dynamic range and particularly for customers of electric utility companies, and it includes a first arm having a first flange portion, a second arm having a second flange portion, and a bridge means coupling the first arm to the second arm wherein the bridge means is a monolithic sintered powdered-metal piece having a block portion and a loop portion. The block portion has a first face juxtaposed to and electrically coupled to the first flange portion of the first arm and a second opposing face juxtaposed to and electrically coupled to the second flange portion of the second arm. This configuration allows a majority of electrical current to conduct between the first arm and the second arm.

Abstract: In the present invention, true volt-amperes reactive power is measured by sampling instantaneous voltage values of voltage and substantially simultaneously instantaneous values of current of an arbitrary waveform, multiplying the voltage samples by the discrete Hilbert transform (corrected by a sign inversion) to obtain voltage samples of all frequencies shifted by -90.degree. over the bandwidth of the signal of interest and then multiplying this quadrature voltage sample by the corresponding current samples to obtain a true value for VARs, i.e., proportional to the instantaneous volt-amperes reactive power under all conditions. The sampling rate and the period of sampling determine the bandwidth and accuracy of the sampling technique. The invention can be implemented in software or in suitable hardware components capable of sampling and delaying the signal of interest.

Abstract: An isothermal current shunt device with excellent temperature coefficient of resistivity characteristics stability for use in a power measuring circuit having a wide temperature and dynamic range and particularly for customers of electric utility companies, and it includes a first arm having a first flange portion, a second arm having a second flange portion, and a bridge means coupling the first arm to the second arm wherein the bridge means is a monolithic sintered powdered-metal piece having a block portion and a loop portion. The block portion has a first face juxtaposed to and electrically coupled to the first flange portion of the first arm and a second opposing face juxtaposed to and electrically coupled to the second flange portion of the second arm. This configuration allows a majority of electrical current to conduct between the first arm and the second arm. The loop portion is outside the first face and the second face of the block portion and conducts a minority of current.

Abstract: A frequency-hopping packet communication system without a master clock or master control unit is based on use of a receiver's frequency hopping timing and identification to control communication. A frequency-hopping band plan, involving the number of channels and the pseudo-random pattern of frequency change and nominal timing of changes, is universally known to each node in the network. A transmitter acquires synchronization with a target node by use of information previously received from or about a target indicating timing of present idle frequency hop of the target receiver. Each receiving node establishes in each station or node a table of receiver frequency hopping sequence offsets (hop timing offsets) of each other node within its communication range, and each node announces its presence on each frequency in a packet with a hop timing offset indicator. The hop timing offset indicator is a key used to read a table to allow nodes to set themselves in synchronization with one another.

Abstract: A packet network routing method and system based on geographic coordinate identifiers is described. Each node in a network is uniquely identified by absolute geographical coordinates or by a code indicating absolute location in an external coordinate-based reference system (node coordinates), and such absolute geographical coordinates or the equivalent are employed as part of a packet identifier for each packet generated for use in making routing decisions. The node coordinates of a local node and its neighboring nodes and the packet coordinates are used by means at each node through which a packet is routed for determining a desired forwarding route of a data packet. The routing may be prioritized according to preselected criteria, preferably achieving maximum forward progress using the least amount of power. The packet routing protocol according to the invention requires no routing directory or table to perform data routing.

Abstract: A frequency-hopping packet communication system without a master clock or master control unit is based on use of a receiver's frequency hopping timing and identification to control communication. A frequency-hopping band plan, involving the number of channels and the pseudo-random pattern of frequency change and nominal timing of changes, is universally known to each node in the network. Frequency-hopping is implemented by the division of communication slots and the accumulation of slots into epochs, wherein each epoch equals the total number of available slots (number of channels times the number of time frames per channel). A transmitting node tracks the preestablished frequency-hopping pattern for its target receiver based on previously-acquired information. The transmission node identifies a receiver node and a current frequency channel of such receiver node. The transmission node then checks the frequency channel to determine if available (e.g., not in use and within an acceptable noise margin).

Abstract: A technique is provided whereby broadcast or flooding packets received at a node are only rebroadcast if specific criteria are met. The criteria are based on a packet routing protocol wherein sequence information is maintained at each node on a link basis for each received packet and wherein received packets are rebroadcast only to other nodes with low sequence numbers. Each node maintains information on each other node within its communication range and assigns a link sequence number to the linked node at the time of the first exchange of a link information packet. Each node works backwards from the information sent to it to determine which other nodes should receive rebroadcast packets. In a packet flooding situation, a node rebroadcasts a flooding packet only to those other nodes which have low sequence numbers or for which the rebroadcasting node is a low sequence number of the other node.

Abstract: Various combinations of three elements are disclosed for use in accurate measurement of power through current measurement over a wide dynamic range, namely, a current shunt which is preferably an isothermal current shunt, a current transformer, which is preferably a high initial permeability current transformer, and a low-impedance burden load, which in the preferred embodiment includes an active negative impedance element which causes the removal of the effects of excitation current by canceling secondary winding resistance of the current transformer. In a specific embodiment of an isothermal current shunt according to the invention, a very linear device is achieved by construction out of copper in such a manner that the poor resistance versus temperature coefficient of copper does not affect the accuracy of measurement. Specifically, the shunt is constructed in an unbalanced isothermal bridge configuration, so that heat-induced variations are suppressed.

Abstract: A packet network routing method and system based on geographic coordinate identifiers is described. Each node in a network is uniquely identified by absolute geographical coordinates or by a code indicating absolute location in an external coordinate-based reference system (node coordinates), and such absolute geographical coordinates or the equivalent are employed as part of a packet identifier for each packet generated for use in making routing decisions. The node coordinates of a local node and its neighboring nodes and the packet coordinates are used by means at each node through which a packet is routed for determining a desired forwarding route of a data packet. The routing may be prioritized according to preselected criteria, preferably achieving maximum forward progress using the least amount of power. The packet routing protocol according to the invention requires no routing directory or table to perform data routing.

Abstract: Various combinations of three elements are disclosed for use in accurate measurement of power through current measurement over a wide dynamic range, namely, a current shunt which is preferably an isothermal current shunt, a current transformer, which is preferably a high initial permeability current transformer, and a low-impedance burden load, which in the preferred embodiment includes an active negative impedance element which causes the removal of the effects of excitation current by canceling secondary winding resistance of the current transformer. In a specific embodiment of an isothermal current shunt according to the invention, a very linear device is achieved by construction out of copper in such a manner that the poor resistance versus temperature coefficient of copper does not affect the accuracy of measurement. Specifically, the shunt is constructed in an unbalanced isothermal bridge configuration, so that heat-induced variations are suppressed.