Full-duplex Communication and Remote Powering Implementation of an Electronic Knee Implant

Full-duplex communication is realized by using ASK modulation for downlink (the channel from controller to the implant) and by using FSK modulation for uplink (from implant to the controller). The ASK modulation is done at the remote powering frequency and by using the inductive link. The class-E type power amplifier is fed by the modulated data. For the uplink communication a stand alone transmitter is designed with a crystal oscillator. The implant node is modeled by using a microcontroller which is sending data and a dummy resistor to mimic the power consumption of the sensors. This microcontroller is also powered up by remote powering.