Microsemi has announced two single-chip, standards-compliant SyncE (synchronous Ethernet) timing devices to allow the transmission of SyncE over OTN (optical transport network) channels without the need for additional rate conversion PLLs. The timing devices support Ethernet clock rates and all OTN clock rates. The timing devices support flexible input and output rates. The programmable digital PLLs in both devices synchronise to a clock rate from 1Hz to 750MHz. This to allow the 1PPS GPS signal to be used directly as an input reference, claims the company. The ZL30154 device provides two independent digital PLLs for applications that require independent transmit and receive timing paths. The ZL30153 device uses a single digital PLL for clock synchronisation. The timing devices require a temperature controlled crystal oscillator to achieve compliance with ITU-T Recommendation G.8262.
