[54] CLOSED-LOOP DOWNLINK TELEMETRY AND METHOD FOR IMPLANTABLE MEDICAL DEVICE
[75] Inventor: John J. Grevious, Minneapolis, Minn.
[73] Assignee: Medtronic, Inc., Minneapolis, Minn.
[21] Appl. No.: 106,495
[22] Filed: Aug. 12,1993
[51] Int. CI.* A61N 1/362
[52] U.S. CI 607/60; 607/32;
128/903
[58] Field of Search 607/32, 60; 128/903
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OTHER PUBLICATIONS
Donaldson, D. den. "Medical & Biological Engineering & Computing" vol. 23, No. 3, May, 1985, p. 291.
Primary Examiner—William E. Kamm
Attorney, Agent, or Firm—Reed A. Duthler; Harold R.
Patton
[57] ABSTRACT
A closed loop system for attaining premium telemetry performance for vector field electromagnetically coupled telemetry systems. The disclosed system utilizes a linear ramped envelope for downlink RF bursts, resulting in a detected pulse width in the implanted device which is proportional to the downlink detection margin. The detected pulse width, when uplink telemetered to an external programming unit allows the programming unit to generate a telemetry status feedback signal for the user positioning the programming head with respect to the implant site. Feedback based upon both uplink and downlink signal strength in especially advantageous in dual-coil systems where there are distinct and unique coupling coefficients for uplink and downlink.
12 Claims, 5 Drawing Sheets
