Closed-loop downlink telemetry and method for implantable medical device
First Claim
1. An implantable medical device system including an implanted device and an external programming unit, said system comprising, in said external unit:
- a downlink radio-frequency (RF) transmitter adapted to transmit RF bursts each having a linear ramped envelope of predetermined duration and of predetermined peak amplitude;
an uplink RF receiver adapted to receive digital information transmitted from said implanted device;
and in said implantable device;
a downlink RF receiver adapted to detect said RF bursts transmitted by said external unit RF transmitter, and RF receiver having a detected signal threshold;
a timing circuit, coupled to said downlink RF receiver and responsive to detection of one of said RF bursts by said downlink RF receiver to generate a digital downlink strength value reflecting the duration of a time interval during which said one detected RF burst exceeds said detected signal threshold;
an uplink RF transmitter, coupled to said timing circuit and adapted to transmit said digital downlink strength value to said external unit.
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Accused Products
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.
323 Citations
12 Claims
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1. An implantable medical device system including an implanted device and an external programming unit, said system comprising, in said external unit:
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a downlink radio-frequency (RF) transmitter adapted to transmit RF bursts each having a linear ramped envelope of predetermined duration and of predetermined peak amplitude; an uplink RF receiver adapted to receive digital information transmitted from said implanted device; and in said implantable device; a downlink RF receiver adapted to detect said RF bursts transmitted by said external unit RF transmitter, and RF receiver having a detected signal threshold; a timing circuit, coupled to said downlink RF receiver and responsive to detection of one of said RF bursts by said downlink RF receiver to generate a digital downlink strength value reflecting the duration of a time interval during which said one detected RF burst exceeds said detected signal threshold; an uplink RF transmitter, coupled to said timing circuit and adapted to transmit said digital downlink strength value to said external unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of controlling the strength, as received, of telemetry signals transmitted in the form of RF bursts from an RF transmitter to an RF receiver having a detected signal threshold, comprising the steps of:
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(a) defining a duration and peak amplitude of a linear-ramping envelope for said RF bursts transmitted from said transmitter; (b) transmitting, from said RF transmitter, an RF burst having said envelope from step (1); (c) detecting, in said RF receiver, said RF burst transmitted in step (b); (d) timing an interval during which said RF burst detected in step (c) exceeds said RF receiver'"'"'s detected signal threshold, to obtain a time value; (e) communicating said time value obtained in step (d) to said RF transmitter; (f) redefining said envelope peak amplitude in inverse proportion to said time value. - View Dependent Claims (12)
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Specification