Patent ID: 8631268

Claim:
A slave device for communicating with a master device, the slave device comprising: a calibration signal generation unit configured to: generate a calibration signal in response to a calibration enable signal generated based on a command from the master device, and send the calibration signal to the master device; a transmission unit configured to: receive a signal from an internal circuit of the slave device only during a time when the calibration enable signal is disabled, and send the signal to the master device through a communication channel; a calibration unit configured to: measure a flight time of the calibration signal that is sent to the master device, and measure a flight time of the calibration signal that is sent back from the master device; and a transmission delay unit configured to: receive the signal sent from the internal circuit of the slave device to the transmission unit, and delay transmission of the signal by the transmission unit by a value based on a measurement result of the calibration unit.