| 摘要 |
In addition to the transmission of a tone signal (ts) according to the RFC standard 2833 via a network using Internet protocol, the tone signal is transmitted in the data packets (dp). Subsequently, the phase difference (&Dgr;&phgr;) between the transmitted tone signal (ts) and the generated tone signal (ts′) is ascertained, before beginning the insertion of the generated tone signal (ts′) in the data packets (dp), and compared to a predetermined phase difference (&phgr;v). If the ascertained phase difference exceeds the predetermined phase difference (&Dgr;&phgr;,&phgr;v), the phase of the generated tone signal (ts′) is changed by a predetermined phase (&phgr;) with the aid of the tone generator (TG). The ascertainment of the phase differences (&Dgr;&phgr;) and the change of the phase (&phgr;) of the generated tone signal (ts′) is repeated until the ascertained phase difference is less than the predetermined phase difference (&Dgr;&phgr;,&phgr;v), upon which instead of the transmitted tone signal (ts), the generated tone signal (ts) is inserted into the data packets (dp). A substantial advantage of the invention can be seen in that a phase detector does not have to be continuously active for the synchronization, but rather the synchronization must only be performed if a tone signal (ts) or tone information (ti) is received and the insertion of the generated tone signal (ts′) is imminent. |
