High speed digital telemetry system for implantable devices
First Claim
1. A telemetry system for use with an implantable device, comprising:
- a DC power source;
an inductor for generating an information-containing magnetic field;
a first capacitor for connection in parallel across said inductor, said first capacitor when connected across said inductor tuning said inductor to a first frequency;
a first switch for selectively connecting said first capacitor in parallel across said inductor when said first switch is closed and disconnecting said first capacitor from parallel connection across said inductor when said first switch is open, said first switch being closed when data is to be transmitted by said inductor;
a second capacitor for connection in parallel across said inductor, said second capacitor when connected across said inductor with said first capacitor also connected across said inductor tuning said inductor to a second frequency;
a second switch for selectively connecting said second capacitor in parallel across said inductor when said second switch is closed and disconnecting said second capacitor from parallel connection across said inductor when said second switch is open, said second switch being open both when no data is to be transmitted by said inductor and when a first digital binary signal is to be transmitted by said inductor, said second switch being closed when a second digital binary signal different from said first digital binary signal is to be transmitted by said inductor, said second switch being opened or closed only when the voltage across said inductor is approximately at either a positive or negative peak value; and
means for periodically, briefly switching said power source into connection across each of said first and second capacitors to charge said first and second capacitors.
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Accused Products
Abstract
A telemetry system for use with implantable medical devices is disclosed which utilizes both in-phase and quadrature data components, and frequency modulates both data components into a single transmitted sinusoidal signal which varies in frequency between two selected frequencies. The signal is received and decoded, preferably by a coherent decoder, into in-phase and quadrature components, which are then integrated and sampled to produce the two transmitted in-phase and quadrature data components, which may then be recombined to produce the transmitted data. The system requires only low power, and is capable of operating at a relatively high data rate while retaining a high degree of accuracy due to the splitting of the signal into the in-phase and quadrature data components.
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Citations
22 Claims
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1. A telemetry system for use with an implantable device, comprising:
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a DC power source; an inductor for generating an information-containing magnetic field; a first capacitor for connection in parallel across said inductor, said first capacitor when connected across said inductor tuning said inductor to a first frequency; a first switch for selectively connecting said first capacitor in parallel across said inductor when said first switch is closed and disconnecting said first capacitor from parallel connection across said inductor when said first switch is open, said first switch being closed when data is to be transmitted by said inductor; a second capacitor for connection in parallel across said inductor, said second capacitor when connected across said inductor with said first capacitor also connected across said inductor tuning said inductor to a second frequency; a second switch for selectively connecting said second capacitor in parallel across said inductor when said second switch is closed and disconnecting said second capacitor from parallel connection across said inductor when said second switch is open, said second switch being open both when no data is to be transmitted by said inductor and when a first digital binary signal is to be transmitted by said inductor, said second switch being closed when a second digital binary signal different from said first digital binary signal is to be transmitted by said inductor, said second switch being opened or closed only when the voltage across said inductor is approximately at either a positive or negative peak value; and means for periodically, briefly switching said power source into connection across each of said first and second capacitors to charge said first and second capacitors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 22)
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19. A telemetry system for use with an implantable device and an external device, comprising:
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a DC power source in said implantable device; an inductor in said implantable device for generating an information-containing magnetic field; a first capacitor in said implantable device for connection in parallel across said inductor, said first capacitor when connected across said inductor tuning said inductor to a first frequency; a first switch in said implantable device for selectively connecting said first capacitor in parallel across said inductor when said first switch is closed and disconnecting said first capacitor from parallel connection across said inductor when said first switch is open, said first switch being closed when data is to be transmitted by said inductor; a second capacitor in said implantable device for connection in parallel across said inductor, said second capacitor when connected across said inductor with said first capacitor also connected across said inductor tuning said inductor to a second frequency; a second switch in said implantable device for selectively connecting said second capacitor in parallel across said inductor when said second switch is closed and disconnecting said second capacitor from parallel connection across said inductor when said second switch is open, said second switch being open both when no data is to be transmitted by said inductor and when a first digital binary signal is to be transmitted by said inductor, said second switch being closed when a second digital binary signal different from said first digital binary signal is to be transmitted by said inductor, said second switch being opened or closed only when the voltage across said inductor is approximatley at either a positive or negative peak value; means in said implantable device for periodically, briefly switching said power source into connection across each of said first and second capacitors to charge said first and second capacitors when said voltage across said inductor is approximately at positive and negative peak values; an external inductor in said external device for either generating an information-containing magnetic field or receiving an information-containing magnetic field a receiver located in said external device for receiving information received by said external inductor. - View Dependent Claims (20)
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21. A method of telemetering data from an implantable device to an external device, comprising:
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generating an information-containing magnetic field with an inductor; selectively tuning said information-containing magnetic field to a first frequency or to a second frequency, said information-containing magnetic field being tuned to said first frequency by connecting a first capacitor across said inductor when a first digital binary signal is to be transmitted by said information-containing magnetic field, said information-containing magnetic field being tuned to said second frequency by connecting both said first capacitor and a second capacitor across said inductor when a second digital binary signal different from said first digital binary signal is to be transmitted by said information-containing magnetic field; periodically, briefly energizing each of said first and second capacitors to charge said first and second capacitors, respectively, when the voltage across said inductor is approximately either a positive or negative peak; and receiving said information-containing magnetic field and deriving the information contained therein therefrom.
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Specification