Systems and devices for equalizing telemetry signals transmitted by way of a transcutaneous narrowband inductive link
An exemplary cochlear implant system includes a sound processor, a cochlear implant, and equalization circuitry integrated within the sound processor and/or the cochlear implant. The sound processor operates externally to a recipient and is associated with a sound processor coil. The cochlear implant includes a cochlear implant coil larger than the sound processor coil and that is configured to form a transcutaneous narrowband inductive link with the sound processor coil when the cochlear implant is implanted within the recipient. By way of the transcutaneous narrowband inductive link, the cochlear implant receives a forward telemetry signal incorporating power and forward telemetry data. The equalization circuitry facilitates recovery, by the cochlear implant, of the forward telemetry data from the forward telemetry signal by compensating for distortion introduced onto the forward telemetry signal as a result of bandwidth limitations imposed by the transcutaneous narrowband inductive link. Corresponding systems and devices are also disclosed.
1. A cochlear implant system comprising:
a sound processor configured to operate externally to a recipient of the cochlear implant system, the sound processor associated with a sound processor coil;
a cochlear implant including a cochlear implant coil configured to form a transcutaneous narrowband inductive link with the sound processor coil when the cochlear implant is implanted within the recipient, the cochlear implant coil having a size larger than a size of the sound processor coil and enabling the cochlear implant to:
receive, from the sound processor by way of the transcutaneous narrowband inductive link, a forward telemetry signal incorporating power for powering operations of the cochlear implant and forward telemetry data for directing the operations of the cochlear implant, and
transmit, to the sound processor by way of the transcutaneous narrowband inductive link, a backward telemetry signal incorporating backward telemetry data;
equalization circuitry integrated within the cochlear implant and configured to facilitate recovery, by the cochlear implant, of the forward telemetry data from the forward telemetry signal by compensating for distortion introduced onto the forward telemetry signal as a result of bandwidth limitations imposed by the transcutaneous narrowband inductive link; and
additional equalization circuitry integrated within the sound processor and configured to facilitate recovery, by the sound processor, of the backward telemetry data from the backward telemetry signal by compensating for distortion introduced onto the backward telemetry signal as a result of the bandwidth limitations imposed by the transcutaneous narrowband inductive link.
2. The cochlear implant system of claim 1 , wherein:
the sound processor is implemented within a single housing; and
the sound processor coil is integrated within the single housing of the sound processor such that the transcutaneous narrowband inductive link formed between the sound processor coil and the cochlear implant coil does not employ a headpiece associated with the sound processor and housed in a separate housing from the sound processor.
3. The cochlear implant system of claim 1 , wherein the forward telemetry signal and the backward telemetry signal are both transmitted on a same carrier frequency.
4. The cochlear implant system of claim 1 , wherein:
the additional equalization circuitry is further configured to compensate, prior to transmission of the forward telemetry signal, the forward telemetry signal for distortion that is to be introduced onto the forward telemetry signal.
5. The cochlear implant system of claim 1 , wherein the forward telemetry signal is generated using an amplitude shift keying protocol whereby the power is delivered as radio frequency (RF) power at a carrier frequency and the forward telemetry data is modulated onto the RF power by adjusting an amplitude of the RF power in a manner that represents digital values of the forward telemetry data.
6. The cochlear implant system of claim 1 , wherein the power incorporated within the forward telemetry signal is delivered as radio frequency (RF) power at a carrier frequency and the forward telemetry data is modulated onto the RF power at a rate exceeding 1.0 megabits per second (mbps).
7. The cochlear implant system of claim 1 , wherein:
the forward telemetry signal further incorporates a clock signal synchronous with the forward telemetry data; and
the cochlear implant coil further enables the cochlear implant to transmit, to the sound processor by way of the transcutaneous narrowband inductive link, a backward telemetry signal incorporating backward telemetry data that is synchronous with the clock signal incorporated in the forward telemetry signal.
8. The cochlear implant system of claim 1 , wherein:
the forward telemetry data is incorporated in a self-clocking data signal modulated onto the power of the forward telemetry signal; and
the self-clocking data signal employs a Manchester encoding to represent both the forward telemetry data and a clock signal synchronous with the forward telemetry data.