Transmitter and transmission/reception system

A transmission/reception system comprising:

• a transmitter that transmits differential signals to a receiver via differential signal lines having AC coupling capacitors provided in middle of the differential signal lines, the transmitter comprising:
• an output driver configured to output the differential signals to the differential signal lines;
• first termination resistors and a first switch, the first termination resistors and the first switch being provided in series between a first reference voltage input terminal and the differential signal lines, a reference voltage being inputted to the first reference voltage input terminal;
• a pulse generator configured to output a common-mode pulse to the differential signal lines during a period during which a pulse output instruction signal is at a significant level;
• and
• a detector configured to output a detection result signal indicating a magnitude relationship between a voltage level of the common-mode pulse and a threshold, during a period during which the pulse output instruction signal is at a significant level, and output a detection result signal indicating that the voltage level of the common-mode pulse does not exceed the threshold, during a period during which the pulse output instruction signal is at a non-significant level,
• wherein the detector includes:
• a comparator having a first input terminal, a second input terminal, and an output terminal and configured to compare magnitudes between a voltage of the common-mode pulse inputted to the first input terminal and a threshold inputted to the second input terminal, and output a comparison result signal from the output terminal, the comparison result signal going to a significant level when the voltage of the common-mode pulse exceeds the threshold;
• and
• a latch circuit configured to continuously output a significant-level signal as the detection result signal after the comparison result signal changes to a significant level during a period during which the pulse output instruction signal is at a significant level;
• and
• a receiver connected to the transmitter by the differential signal lines, wherein
• the receiver includes:
• an input buffer configured to accept, as input, differential signals arriving from the transmitter via the differential signal lines;
• and second termination resistors and a forth switch, the second termination resistors and the forth switch being provided in series between a second reference voltage input terminal and the differential signal lines, a reference voltage being inputted to the second reference voltage input terminal.