| 摘要 |
PROBLEM TO BE SOLVED: To secure a sound quality within a channel bandwidth range limited by a digital signal in a wireless system for municipal administration dealing with prevention of disaster composed of a master station and a plurality of slave stations for receiving radio waves concerning the municipal prevention of disasters transmitted from the master station through radio within a limited frequency band and reproducing audio. SOLUTION: In the master station, audio is encoded at a high sampling speed with a sample value, an encoded signal is stored in a storage means, the value of time to start transmission before broadcasting starting time is calculated on the basis of the designated broadcasting starting time, an effective transmission velocity in a radio space and the speed of an encoding means when the broadcasting starting time is designated, and transmission is started before the broadcasting starting time just for the calculated time period. In each of slave stations, information transmitted from the master station is stored in a storage means at the effective transmission velocity in the radio space, the signal in the storage means is read and decoded at the speed of the encoding means in the master station, and audio is outputted.
|
