Transmitting circuit, communication system, and communication method

A transmitting circuit comprising:

• a first driver circuit configured to receive a first digital signal of a predetermined cycle length and a predetermined data rate and output a signal corresponding to the first digital signal in a first state, and receive a third digital signal obtained by alternately synthesizing the first digital signal with a second digital signal, shifted by a half of the predetermined cycle length from the first digital signal, of the predetermined cycle length and the predetermined data rate so as to ensure that a data rate of the third digital signal is twice as high as the data rate of the first digital signal and output a signal corresponding to the third digital signal in a second state that is different from the first state;
• and
• a second driver circuit configured to receive the second digital signal and output a signal corresponding to the second digital signal in the first state, and output the signal corresponding to the third digital signal in the second state,
• wherein an output of the first driver circuit is coupled to an output of the second driver circuit,
• wherein in the first state, the outputs coupled represent a maximum level or a minimum level if a value of the first digital signal is equal to a value of the second digital signal, and the outputs coupled represent a level between the maximum level and the minimum level if the value of the first digital signal is different from the value of the second digital signal, and
• wherein in the second state, the outputs coupled represent a level corresponding to a high or low level of the third digital signal.

A communication system comprising:

• a transmitting circuit;
• a transmission path of which an end is coupled to an output unit of the transmitting circuit;
• and
• a receiving circuit coupled to another end of the transmission path,
• wherein the transmitting circuit includes
• a multiplexer configured to output a third digital signal obtained by alternately synthesizing a first digital signal of a predetermined cycle length and a predetermined data rate with a second digital signal, shifted by a half of the predetermined cycle length from the first digital signal, of the predetermined cycle length and the predetermined data rate so as to ensure that a data rate of the third digital signal is twice as high as the data rate of the first digital signal,
• a first selector configured to output the first digital signal in a first state and output the third digital signal in a second state that is different from the first state,
• a second selector configured to output the second digital signal in the first state and output the third digital signal in the second state,
• a first driver circuit configured to output a signal corresponding to a signal output from the first selector, and
• a second driver circuit coupled to the first driver through outputs of the first and second driver circuits and configured to output a signal corresponding to a signal output from the second selector.

A communication method comprising:

• transmitting a signal obtained by synthesizing an output signal corresponding to a first digital signal of a predetermined cycle length and a predetermined data rate with an output signal corresponding to a second digital signal, shifted by a half of the predetermined cycle length from the first digital signal, of the predetermined cycle length and the predetermined data rate in a first state;
• transmitting a signal corresponding to a third digital signal obtained by alternately synthesizing the first digital signal with the second digital signal so as to ensure that a data rate of the third digital signal is twice as high as the data rate of the first digital signal in a second state that is different from the first state;
• and
• receiving the signals transmitted in the first and second states.