Method of nerve stimulation and a stimulator for the application of the method

A stimulator for implantation in a living body and there delivering, by means of electrodes, pulses which are capable of electrically exciting living cells in response to a frequency modulated electromagnetic transmitter external to said living body, said stimulator comprising, in combination:

• a receiving coil tuned to a predetermined reference frequency f.sub.0 ;
• first detecting means responsive to the output of the receiving coil for delivering a continuous d.c. signal having a duration equal to the duration of an alternating current signal obtained at the output of the receiving coil;
• stabilizing circuit means responsive to said first detecting means for providing a continuous d.c. output signal having a constant as well as a duration equal to the duration of said alternating current signal;
• frequency detection means, having a first input connected for response to the output of said receiving coil and having a second input connected to the output of said stabilizing circuit, for delivering an output signal having a magnitude which is proportional to the difference between the detected frequency f and said reference frequency f.sub.0 during a time interval t equal to the duration of said alternating current signal obtained at the output of the receiving coil and for delivering no significant output at other times;
• pulse shaping circuit means for producing a cell stimulating pulse in response to the output of said frequency detection means, having a control input connected to the output of said frequency detection means, said pulse having an amplitude which is proportional to said frequency difference f -f.sub.0 and a duration determined by said time interval t, and
• output means, including electrodes implanted in said living body, responsive to the output of said pulse shaping circuit means for providing cell stimulating pulses to living cells adjacent to said electrodes.