modulated signal from modulator 510 the modulated light may be detected and demodulated by wand 108 to recover the data stored in memory 206 as described above in one embodiment power converter 508 employs a full wave rectifier to convert the currents induced in coil 502 into a unidirectional charging current the power converter also includes a bank of switching capacitors to be charged by the unidirectional charging current and thereafter step up the voltage to charge an energy storage capacitor current sensor 504 may be configured to detect the induced currents by sensing the voltage drop across one or more diodes in the full wave rectifier in another embodiment the led is powered by power supply 202 of pacer 106 power converter 508 may be included for the purpose of recharging power supply 202 various modulation schemes may be employed for the communication channels the wand to implant communications channel may use pulse width modulation pwm frequency shift keying fsk or other suitable techniques the implant to wand communications channel may also employ any suitable techniques such as pulsecode modulation pcm and simplex signaling both channels may employ channel coding for error detection timing and or constraining power usage such.