Abstract: A non-reflective ring topology MPNT switching device comprises at least two poles, at least four throws, plural main switches, and plural bridge switches. The bridge switches enable all throws to be non-reflective throughout a wide frequency range. Each main switch is connected between one of the poles and one of the throws. Each bridge switch is connected between two of the throws, and each throw is connected to at least M+1 of the bridge switches, M being the pole count. In operation, each of M of the main switches has a first (ON) state and is connected to one of M active throws. For each active throw, each bridge switch connected to the active throw has a second (OFF) state. For each non-active throw, one bridge switch connected to the non-active throw has the first (ON) state and each other connected bridge switch has the second (OFF) state.

Abstract: A high isolation electronic multiple pole multiple throw (MPNT) switching device is formed as a ring circuit that includes plural poles, plural throws, plural series switches and plural means for shunting. Each series switch receives a control signal, and each means for shunting receives shunt control signals. In one aspect, the shunt control signals include control signals received by distant series switches. In another aspect, the shunt control signals include control signals received by adjacent series switches. In another aspect, the shunt control signals include signals complementary to signals received by adjacent series switches. In another aspect, the shunt control signals include pole DC potentials or throw DC potentials. In another aspect, a switching device may operate in multiple transmission mode or multiple input multiple output (MIMO) mode. The MPNT switching device provides low insertion loss and high isolation at a wide range of frequencies.

Abstract: A monitoring system comprises a specific remote unit or monitor and a plurality of base stations that are capable of communicating with one another. A designated one of the plurality of base stations transmits a message via a wireless medium to the specific remote unit on behalf of the plurality of base stations, and the plurality of base stations use a shared base station identifier or shared sender address for communication with the specific remote unit or monitor. In another aspect, a first designated one transmits a message during a first time period and a second designated one transmits a message during a second time period. Receiving messages from a designated one of the plurality of base stations using the shared base station identifier helps the specific remote unit or monitor to reduce its power usage.

Abstract: An apparatus for determining a characteristic for a fluid in a tube, the apparatus including a force applying system to cause a change in a transverse dimension of a segment of the tube, wherein the change in the transverse dimension is reversible, and an ultrasonic system that comprises a single transducer for launching and receiving ultrasonic signals. Ultrasonic signals propagate through the tube along colinear paths of different lengths that are orthogonal to the tube wall. At least one of the paths is located entirely within the segment. Each of the ultrasonic signals propagates through the tube wall in a first wall region and reflects from an inner surface of a second wall region. Path length differences between the paths are determined, and transit times are determined for each of the ultrasonic signals. The characteristic is determined based on information including the path length differences and the transit times.