Tissue Stimulators Utilizing Radiofrequency Coupling

Abstract

Voltages of arbitrary wave forms, such as those employed for stimulating biological tissues, are normally obtained from ``grounded'' signal generators. Isolation of such signals from ground can be accomplished by utilizing radiofrequency transmission of energy. The signal generator voltage serves as the source of plate power for a midget radiofrequency oscillator which converts the signal to amplitude‐modulated carrier energy. This radiofrequency energy is then transmitted across a small air gap to a receiving circuit where it is demodulated and filtered. The voltage thus recovered is a faithful reproduction of the original signal but is isolated from the input circuit as well as from ground. One model of this radiofrequency link which was developed for nerve stimulation and which has performed well in the laboratory is described in detail.