Patent ID: 7610065

Claim:
A system for communicating with an implantable medical device, the system comprising: a diversity antenna system including a plurality of antennas configured to transmit an outgoing signal to the implantable medical device and to receive an incoming signal from the implantable medical device; a transceiver adapted to transmit outgoing data frames by modulating the outgoing signal and to receive incoming data frames by demodulating the incoming signal, the outgoing data frames and the incoming data frames each being a unit of data including a header, a payload, and a trailer; an antenna interface circuit coupled between the diversity antenna system and the transceiver, the antenna interface circuit including a switch circuit adapted to connect an antenna of the diversity antenna system to the transceiver according to an antenna selection signal; and an antenna control circuit adapted to produce the antenna selection signal, the antenna control circuit including: a fading detector coupled to the transceiver, the fading detector adapted to detect a transmission failure deemed to be associated with a null, the fading detector including an incoming frame failure detector adapted to detect an incoming frame failure being a data transmission error in at least one frame of the incoming data frames, the incoming frame failure detector including a lack-of-comma detector adapted to detect a comma indicative of a receipt of a frame of the incoming data frames during a predetermined time window and to indicate the incoming frame failure if the comma is not detected during the predetermined time window; an antenna selector coupled to the fading detector, the antenna selector adapted to adjust the antenna selection signal for connecting a different antenna of the diversity antenna system to the transceiver in response to a detection of the transmission failure including the incoming frame failure; and an antenna switching timing circuit coupled between the antenna selector and the switch circuit, the antenna switching timing circuit adapted to hold the antenna selection signal such that the antenna of the diversity antenna system remains connected to the transceiver while a frame of the outgoing data frames is being transmitted or a frame of the incoming data frames is being received.