Digital data transmitting apparatus, digital data receiving apparatus, and digital data communication apparatus

摘要

In order to effectively use a band and securely transmit emergency information such as information of disasters because such information needs to be securely provided to a user most preferentially via a digital broadcasting receiver held by the user even when the user is outside, digital data is multiplexed on the basis of transmission volume of the digital data, and data type, priority and data effective time as attributes of the digital data, and the multiplexed digital data is transmitted.