Transmission apparatus and transmission method

A transmission apparatus comprising:

• a first transponder configured to use a first path for communication when electric power is supplied;
• a second transponder configured to use a second path for communication when electric power is supplied;
• a detector configured to detect a fault predictive sign;
• a controller configured to supply no electric power to the second transponder when the detector does not detect the fault predictive sign, and start supplying electric power to the second transponder and perform normality confirmation of the second path when the detector detects the fault predictive sign, before switching from the first path to the second path;
• a delay adjuster configured to adjust a delay difference between a signal received by the first transponder and a signal received by the second transponder to be equal to or less than a predetermined delay difference, and output the signals with the adjusted delay difference to the selector;
• a selector configured to select and output, when the first transponder and the second transponder have received signals, either the signal received by the first transponder or the signal received by the second transponder;
• and
• wherein the controller performs switching from the first path to the second path, in response to a path switching trigger occurring after normality is confirmed by the normality confirmation, and
• the selector selects and outputs the signal received by the first transponder before the switching to the second path, and selects and outputs the signal received by the second transponder after the switching to the second path.