Patent ID: 7602868

Claim:
An asynchronous transmission device that receives at least one notification signal in accordance with a reception clock, the notification signal being transmitted in accordance with a transmission clock, said device comprising: a trigger signal transmission unit that outputs a trigger signal which is based on a symbol period of the notification signal; a notification signal transmission unit that outputs a notification signal which has its timing staggered by a predetermined time period with respect to the timing of the trigger signal output from the trigger signal transmission unit; a trigger signal synchronization unit that synchronizes the trigger signal, and outputs a sampling timing signal which indicates a sampling timing of the notification signal; and a notification signal retention unit that retains the notification signal in accordance with the sampling timing; wherein the notification signal has a value changing at a constant period; the trigger signal has a value changing at the constant period; the constant period is a plurality of times of a period of the transmission clock; and the trigger signal synchronization unit has a plurality of synchronization flip-flops which are serially connected, detects a change timing of the synchronized trigger signal, and outputs the change timing thus detected as the sampling timing signal.