| 摘要 |
PURPOSE: To process data whose phase is arbitrarily different from that of a system clock transmitted form a subscriber station by providing an exchange with a delay line, which receives an input data cell and selecting a tap, which keeps the most suitably synchronized data with a master clock, from different taps of a delay line. CONSTITUTION: A central exchange 1 transfers packets of data to subscriber stations 3 at a rate determined by a master clock 5. Each subscriber station 3 uses normal PLL to reproduce the master clock from received data packets and returns data to the central exchange 1 with its frequency. The central exchange 1 has a phase alignment system on the reception side. The phase alignment system is provided with a delay line 7 for reception of input data and an eye position detection circuit 9 and uses the delay line 7 to gradually delay data and specifies the tap, which has data of a phase suitable for the master clock, from the delay line 7. |
