Acquisition circuit for cardiac pacer
First Claim
1. A cardiac pacing system including an acquisition circuit for a cardiac pacer to indicate when an external telemetry head is adequately positioned over an electronic stimulator implanted in a human body for data transmission comprising:
- oscillator means for producing an externally generated magnetic signal at a first predetermined frequency;
enabling means for generating a second signal at a second predetermined frequency which is lower than said magnetic signal;
drive means for combining said magnetic and second signals to provide a third signal containing said second signal enveloping said magnetic signal for each half cycle;
an implantable pacer including an inductor coil means tuned to said magnetic signal frequency for generating an induced signal in the presence of said magnetic signal at the same frequency to which said coil means in tuned, means for providing, to said induced signal, a phase-shift relative to said magnetic signal dependent upon the distance of said pacer to said telemetry head;
circuit means responsive to said magnetic signal and said induced signal for generating pulse signals when said telemetry head is over said electronic stimulator; and
indicating means coupled to said circuit means for transmitting signals changing from pulsing to a steady on condition as the pulses from said circuit means increase when said telemetry head is moved closer to and adequately positioned over said implant to indicate that positive acquisition has been obtained.
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Accused Products
Abstract
An acquisition circuit for a cardiac pacer includes an oscillator for producing an externally generated magnetic signal at a first predetermined frequency. An implantable cardiac pacer has a tuned inductor coil to be responsive to the magnetic signal for developing an induced signal with a phase-shift. Light-emitting devices are responsive to the magnetic signal and the induced signal are provided for transmitting optical signals which change gradually from flashing to a steady on condition when the telemetry head is moved closer to and adequately positioned over the cardiac pacer to indicate that positive acquisition has been obtained.
310 Citations
16 Claims
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1. A cardiac pacing system including an acquisition circuit for a cardiac pacer to indicate when an external telemetry head is adequately positioned over an electronic stimulator implanted in a human body for data transmission comprising:
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oscillator means for producing an externally generated magnetic signal at a first predetermined frequency; enabling means for generating a second signal at a second predetermined frequency which is lower than said magnetic signal; drive means for combining said magnetic and second signals to provide a third signal containing said second signal enveloping said magnetic signal for each half cycle; an implantable pacer including an inductor coil means tuned to said magnetic signal frequency for generating an induced signal in the presence of said magnetic signal at the same frequency to which said coil means in tuned, means for providing, to said induced signal, a phase-shift relative to said magnetic signal dependent upon the distance of said pacer to said telemetry head; circuit means responsive to said magnetic signal and said induced signal for generating pulse signals when said telemetry head is over said electronic stimulator; and indicating means coupled to said circuit means for transmitting signals changing from pulsing to a steady on condition as the pulses from said circuit means increase when said telemetry head is moved closer to and adequately positioned over said implant to indicate that positive acquisition has been obtained. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A cardiac pacing system including an acquisition circuit for a cardiac pacer to indicate when an external telemetry head is adequately positioned over an electronic stimulator implanted in a human body for data transmission comprising:
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a telemetry head including acquisition circuit means for indicating when said telemetry head is adequately positioned over an implanted cardiac pacer; said acquisition circuit means including oscillator means for producing an externally generated magnetic signal at a first predetermined frequency; enabling means for generating a second signal at a second predetermined frequency which is lower than said magnetic frequency; an implantable cardiac pacer including inductor means to be responsive to said magnetic signal for developing an induced signal with a phase shift; and said acquisition circuit further includes indicating means for transmitting optical signals changing from flashing to a steady on condition when said telemetry head is moved closer to and is adequately positioned over said cardiac pacer to indicate that positive acquisition has been obtained, said indicating means providing a flashing rate in inverse proportion to the proximity of the telemetry head to said cardiac pacer. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A cardiac pacing system including an acquisition circuit for use in an implantable telemetry system comprising:
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an external telemetry head including oscillator means for producing an externally generated magnetic signal at a predetermined frequency; an implanted cardiac pacer including inductor means responsive to said magnetic signal for developing a re-radiated signal with a phase shift relative to said magnetic signal dependent upon the distance of said pacer to said telemetry head; and said telemetry head further including indicating means responsive to said magnetic signal and said re-radiated signal for transmitting optical signals changing from flashing to a steady on condition when said telemetry head is moved closer to and adequately positioned over said cardiac pacer to indicate that positive acquisition has been obtained, said indicating means providing a flashing rate in inverse proportion to the proximity of the telemetry head to said cardiac pacer.
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Specification