Abstract: A status monitoring system for evaluating the condition of an electrode implanted in the body of a mammal. The system comprises a modulator for modulating interrogation signals on an electrode of an implanted device, and a monitor for analyzing modulated interrogation signals being reflected by the electrode. The monitor comprises a transmitter for transmitting interrogation signals, a receiver for receiving and processing the signals reflected by the electrode, and a microprocessor for controlling the transmitter and the receiver. The microprocessor producing electrode condition data from the signals processed by the receiver. The invention further comprises a communication system in communication with the monitoring device for transmitting the electrode condition data to a remote location. The interrogation signals are transmitted by the transmitter onto the electrode. The interrogation signals are modulated on the electrode by combining with a modulation signal generated by the modulator.

Abstract: A telemetry system includes a remote monitoring station, a repeater worn externally by a patient and a quasi-passive transponder attached to a device implanted in the patient. The remote monitoring station communicates to the repeater to initiate an interrogation routine between the repeater and the transponder to extract patient condition information from the implanted device. When the repeater receives the condition information, it relays it to the remote monitoring station. The transponder is specially designed to operate with an extremely low level of power, less than 1 nW/baud, and to be compatible for attachment to existing implanted devices. The transponder can operate at a very high data rate, including a rate of about 100 kbps.

Abstract: A spiral antenna has a plurality of interleaved radiating elements winding outwardly in a spiral pattern about a common axis. The spiral pattern is deformed at outer regions of the antenna to define one or more circumferentially disposed concavities in the body of the antenna. Each concavity is adapted to receive another antenna such as a spiral antenna or horn antenna.

Abstract: Frequency scanning means and method comprising a broadband signal discriminator means for receiving and delivering signals within its frequency band, detecting means receiving signals delivered by the discriminator means and providing output signals related to the frequencies of the received signals, signal generating means selectively providing output signals corresponding to the frequencies of signals within the band of said discriminator means, and signal processing means receiving the output signals of said detecting means and said generating means and delivering an output signal for each signal delivered by said discriminator means having a frequency selected by said generating means, and including gating means receiving signals from the discriminator means and the processing means and delivering signals from the discriminator means during receipt by the gating means of signals from the processing means.