Apparatus for transmission of information by electrocutaneous stimulus

Abstract

In the transmission of information through the medium of electrocutaneous stimuli, the data is generally transmitted by issuing signals in the form of pulse trains which carry the information in terms of their frequency of repetition, the duration time of the train of pulses, the pulse height and the pulse width. Different pulse signals, on conveyance to the organism, generate thereon one and the same magnitude of sensation when the products of pulse widths multiplied by the squares of respective pulse heights are equal. By a procedure of first measuring the cutaneous impedance of a given subject, forwarding the measured value of impedance as a feedback for thereby controlling the pulse signal of the information being transmitted so as to make constant the product of the pulse width multiplied by the square of the pulse height of the pulse signals and passing the controlled pulse signal to the subject, the magnitude of sensation roused in response to any particular signal is rendered constant at all times and therefore the information conveyed through the medium of a varying collection of such particular signals can be correctly transmitted to the subject.