Patent ID: 8638841

Claim:
A transmitting/receiving system comprising: a pair of transmitting/receiving apparatuses that are connected to each other through a transmission cable having first and second signal lines, through each of which a signal is transmitted in one direction, each of the transmitting/receiving apparatuses including a transmitting unit that transmits the signal through a corresponding one of the first and second signal lines, a receiving unit that receives the signal through a corresponding one of the first and second signal lines, a calculator that calculates a signal-to-noise ratio of the signal received through a corresponding one of the first and second signal lines by the receiving unit, a controller that controls the calculator to calculate the signal-to-noise ratio by obtaining a strength of a signal as a first value, the signal being received by the receiving unit when the transmitting unit transmits a check signal through a corresponding one of the first and second signal lines in a state in which the receiving unit has not received a check signal through a corresponding one of the first and second signal lines, obtaining a signal strength as a second value, the signal strength being obtained when the check signal is received through a corresponding one of the first and second signal lines by the receiving unit in the state in which the transmitting unit does not transmit a check signal through a corresponding one of the first and second signal lines, and dividing the second value by the first value, a storage unit that stores relationship information about a relationship between a signal-to-noise ratio measured in advance only for the transmission cable and temporal fluctuation of a signal, and an estimating unit that estimates a temporal fluctuation of a signal transmitted through the transmission cable connecting the pair of the transmitting/receiving apparatuses, from the signal-to-noise ratio calculated by the calculator and the relationship information stored in the storage unit.