Abstract: Dynamically switching between different external RF transceivers for communication with an implantable medical device maintains high communication quality in the face of interference, fading, detuning, or other adverse wireless communication conditions. Quality information associated with communications between an implantable medical device and different external devices is monitored to select one of these external devices to conduct subsequent communication with the implantable medical device. This monitoring is conducted on a repeated basis such that communication is switched to a different RF transceiver whenever such an RF transceiver is able to achieve a higher quality communication than the currently selected RF transceiver. In some embodiments, RF transceivers are deployed in different devices. For example, one or more RF transceivers may be deployed at a portable programmer (e.g., in the form of a computer tablet) and one or more other RF transceivers may be deployed at an associated base station.

Abstract: Dynamically switching between different external RF transceivers for communication with an implantable medical device maintains high communication quality in the face of interference, fading, detuning, or other adverse wireless communication conditions. Quality information associated with communications between an implantable medical device and different external devices is monitored to select one,of these external devices to conduct subsequent communication with the implantable medical device. This monitoring is conducted on a repeated basis such that communication is switched to a different RF transceiver whenever such an RF transceiver is able to achieve a higher quality communication than the currently selected RF transceiver. In some embodiments, RF transceivers are deployed in different devices. For example, one or more RF transceivers may be deployed at a portable programmer (e.g., in the form of a computer tablet) and one or more other RF transceivers may be deployed at an associated base station.

Abstract: An implantable cardiac stimulation device is equipped with a hardware elastic buffer. In an exemplary device, the hardware elastic buffer comprises SRAM and a SRAM controller. The device optionally includes averaging, concatenating, filling and/or other features.

Abstract: An implantable cardiac stimulation device includes a system for detecting noise in an electrogram signal. The system for detecting noise generates an event signal when the electrogram signal exceeds a threshold. A timer times a refractory time period responsive to an event signal. During the refractory time period, a zero crossing detector generates a zero crossing signal when the electrogram signal transitions between positive and negative values. A counter counts the zero crossing signals during the time period and a comparator determines if the counter reached a predetermined count during the time period. If the counter exceeds a programmable count, a noise detection flag is set and the controller is alerted to the presence of noise in its input signal.

Abstract: A system for determining the location of a mobile transmitter is disclosed. The mobile transmitter receives a message signal and responds to the message signal by transmitting a responsive signal, wherein the responsive signal is indicative of the identity of the mobile transmitter. One preferred embodiment comprises at least three antenna site systems 10, a central site system 12, a database processor for use in connection with various applications, and a map system 16. The system may be employed to locate cellular telephones and/or like devices emitting bursty transmissions, e.g., over messaging or control channels.

Abstract: In a method and system for locating an unknown transmitter which emits an interfering signal, multiple signals, including a phase-calibrating signal and the interfering signal, are simultaneously observed within a passband. These signals are then simultaneously cross-correlated. The phase-calibrating signal is then isolated from the cross-correlated signals and processed to determine an amount of offset to compensate for frequency fluctuations between local oscillators in satellites, which receive and retransmit the phase-calibrating signal and the interfering signal.

Abstract: A satellite tracking system, including a terrestrial transmitter, a plurality of terrestrial receivers, and a controller/analyzer, operates in two modes. In an active mode, the transmitter emits a tracking signal within a spread spectrum to a satellite and at least one of the receivers receives the signal retransmitted by the satellite. The controller/analyzer then determines the satellite position and velocity from the received signal. In a passive mode, at least two receivers each receive a signal transmitted from the satellite during normal operation and the controller/analyzer determines the satellite position and velocity from the received signals. The satellite position and velocity can be used to determine the position of an unknown transmitter that causes interference at the satellite.

Abstract: A cellular telephone location system for automatically recording the location of one or more mobile cellular telephones comprises three or more cell site systems 12. Each cell site system is located at a cell site of a cellular telephone system. Each cell site system includes an antenna that may be mounted on the same tower or building as the antenna employed by the cellular telephone system and equipment that may be housed in the equipment enclosure of the corresponding cell site. The cell site systems are coupled via T1 communication links 14 to a central site 16. The central site may be collocated with the cellular telephone system's MTSO. The central site 16 is further coupled to a database 20, which may be remotely located from the central site and made available to subscribers.