Patent attributes
A transmitter comprising: a signal modulator for transmitting electrical signals via an electrode, wherein the electrical signals carry a message representing a signal value; and a controller, coupled to the signal modulator, configured for having the signal modulator transmitting the electrical signals with a first duty cycle in a reference signal time period and transmitting the electrical signals with a second duty cycle in a modulation signal time period, wherein a first ratio corresponding to the second duty cycle and the first duty cycle is corresponding to the signal value, wherein the lengths of the reference signal time period and the modulation signal time period are the same, and wherein the maximum amplitudes of the electrical signals during the reference signal time period and the modulation signal time period are the same.
