Patent ID: 8705599

Claim:
A method for quantification of a desynchronization between two clocks of a system comprising at least two active implantable medical devices that communicate wirelessly, including: a first active implantable medical device comprising a first slow clock having a slow clock pulse rate, a first transmitter/receiver, and a first digital processing circuit clocked by the first slow clock; and a second active implantable medical device comprising a second slow clock having said slow clock pulse rate, a second transmitter/receiver, and a second digital processing circuit clocked by the second slow clock, wherein the first active implantable medical device and the second active implantable medical device are configured to communicate wirelessly by human body communication signals (HBC signals), wherein the HBC signals comprise pulse trains conducted by interstitial tissues of the body, and wherein the first transmitter/receiver and the second transmitter/receiver are configured to transmit and receive the HBC signals; wherein the first active implantable medical device includes a first fast clock having a fast clock pulse rate, the fast clock pulse rate being faster than the slow clock pulse rate; the quantification method comprising the steps of: a) at the second active implantable medical device, detecting a predetermined transition of a pulse of the second slow clock, and in response thereto transmitting from the second active implantable medical device to the first active implantable medical device a synchronization query; b) at the first active implantable medical device, detecting said synchronization query and a predetermined transition of a pulse of said first slow clock, and counting a first number of pulses of the first fast clock occurring between said detected synchronization query and said detected predetermined transition of the pulse of the first slow clock; then c) in response to counting said first number of pulses, transmitting from the first active implantable medical device to the second active implantable medical device a response signal to the synchronization query, wherein the response signal includes a result corresponding to the counted first number; and d) receiving at the second active implantable medical device, the response signal to the synchronization query, and computing a temporal shift (OFFSET) corresponding to a desynchronization based on said counted first number of fast clock pulses; wherein step b) further comprises selectively activating the first fast clock before the start of counting of the first fast clock pulses, and deactivating the first fast clock after detection of the predetermined transition of the pulse of the first slow clock.