Patent ID: 8112002

Claim:
A transmitting circuit comprising: a first transmitter configured to generate a first electric pulse signal in synchronization with a rising edge of a digital electric input signal by combining at least one of the digital electric input signal and an inverted signal of the digital electric input signal with at least one of a first delay signal obtained by delaying the digital electric input signal by a time shorter than a minimum pulse width of the digital electric input signal and a second delay signal obtained by delaying the inverted signal of the digital electric input signal by a time shorter than the minimum pulse width of the digital electric input signal; a second transmitter configured to generate a second electric pulse signal in synchronization with a falling edge of the digital electric input signal by combining at least one of the digital electric input signal and the inverted signal of the digital electric input signal with at least one of the first delay signal and the second delay signal; a first variable impedance circuit configured to supply a bias current to a first light-emitting element only for a predetermined period before the first light-emitting element for converting the first electric pulse signal into a first light signal is supplied with the first electric pulse signal; and a second variable impedance circuit configured to supply a bias current to a second light-emitting element only for a predetermined period before the second light-emitting element for converting the second electric pulse signal into a second light signal is supplied with the second electric pulse signal.