Signal transmission means

This invention is provided with: a modulation signal convertor (1) for generating, in accordance with transmitted data, a modulation signal that uses a Manchester code with a 50% duty cycle; a clock generator (6) for generating a clock, which is an amount of delay with respect to either the leading edge or the trailing edge of the modulation signal; and a data detector (5) for sampling the modulation signal in synchronization with the clock to generate received data. The modulation signal convertor (1), in order to generate a modulation signal in combination with a 50% duty cycle Manchester code, maintains the duty cycle at a constant 50% regardless of the transmitted data to prevent a DC offset in the reception system modulation signal. Therefore, the effect is that good communication quality is achieved with a simple circuit configuration without DC offset occurring in the reception system modulation signal.