| 摘要 |
PURPOSE:To synchronize a reference signal with an input signal in a short time after channel switching by storing differential frequency information between input signals of individual channel of a time division multiple signal and the reference signal independently and synthesizing differential frequency information and a phase error signal to control the phase of the reference signal at a channel switching time. CONSTITUTION:A phase comparing circuit 1 outputs a demodulated signal So and a phase error signal e0 in accordance with an input signal Si, which is obtained by multiplexing burst signals of individual channels in time division, and a reference signal Sr from a sine wave-cosine wave converting circuit 4. A loop filter 2 smooths the signal e0 to output an error signal e0'. In this case, the output of a synthesizing circuit 13 is stored in a storage circuit 14 as differential frequency information between signals Si and Sr. At this time, storage areas MA-Mi of the storage circuit 14 corresponding to channels are selected by switching circuits 15 and 16. A signal generating circuit 3 generates a phase signal Sp on a basis of the signal e0'. Said differential frequency information is taken out selectively in accordance with coming channels of the input signal. Since this information is varied continuously with respect to the same channel, it is synchronized quickly at a channel switching time. |
