Abstract: A multi-input voltage-to-frequency conversion circuit includes: a multi-input operational amplifier amplifying one of multiple voltage signals in response to multiple control signals to generate an amplified voltage; a voltage-to-current converter converting the amplified voltage into a sensed current, and generating an oscillation current based on the sensed current and on an offset voltage that is associated with a predetermined frequency range corresponding to the one of the voltage signals; and a current-controlled oscillator generating, based on the oscillation current, a periodic pulse signal that has a frequency linearly proportional to the magnitude of the one of the voltage signals.

Abstract: In a real-time information transmission and reception system, a transmission device includes a light emitter driven by a modulated control signal generated by a modulation controller based on a code sequence, which is encoded from an input signal generated by an input unit and corresponding to information to be transmitted, to emit light. The modulated control signal has a constant average power, and various frequencies greater than 60 Hz. A reception device includes a photoelectric sensor for sensing the light emitted by the light emitter to generate a current signal that is demodulated and processed to generate a data output corresponding to the information and received by a display unit for displaying the information thereon.

Abstract: In a real-time information transmission and reception system, a transmission device includes a light emitter driven by a modulated control signal generated by a modulation controller based on a code sequence, which is encoded from an input signal generated by an input unit and corresponding to information to be transmitted, to emit light. The modulated control signal has a constant average power, and various frequencies greater than 60 Hz. A reception device includes a photoelectric sensor for sensing the light emitted by the light emitter to generate a current signal that is demodulated and processed to generate a data output corresponding to the information and received by a display unit for displaying the information thereon.