IEEE 1588 time/frequency generators disciplined by synchronous Ethernet

October 02, 2014 // By Graham Prophet
IDT's time and frequency generator chips use physical layer frequency support to stabilise low-cost oscillators creating highly stable frequency references for IEEE 1588 clock recovery software

A family of IEEE 1588 time and frequency generator chips, they can reduce costs while meeting the synchronisation needs of LTE-Advanced, wireless backhaul and heterogeneous networks. The architecture and capabilities of these devices are fully documented and accessible to allow IEEE 1588 software designers to implement their own clock recovery algorithms and add value through customisation and quick turnaround support.

These chips include synchronisation management devices (SMDs) and port synchronisers for IEEE 1588 and synchronous Ethernet (SyncE). The SMDs manage IEEE 1588 time and frequency generation and SyncE synchronisation. The port synchronisers select between redundant SMD signals and provide accurate time and low-jitter clocks to the network ports in the system.

The IDT 82P33810, 82P33814 and 82P33831 SMDs reduce the cost of IEEE 1588 clocks by replacing stable but expensive oven-controlled crystal oscillators (OCXOs) with low-cost temperature-compensated crystal oscillators (TCXOs) that are stabilised with frequency information from the SyncE physical layer. The process of stabilising the TCXOs is automatic and transparent to the IEEE 1588 clock recovery software.

The IDT 82P33724 and 82P33741 port synchronisers provide independent timing channels for IEEE 1588 and SyncE; a third independent timing channel is provided for general purpose rate conversion. Hitless reference switching is supported between redundant IEEE 1588 references and between redundant SyncE references. These devices manage IEEE 1588 time and frequency references by accepting clocks paired with 1 pulse per second (1 PPS) sync signals.

IDT says that in addition to providing cost savings by enabling the use of TCXOs, these devices deliver the lowest jitter of any IEEE 1588 clock generators on the market. The SMDs cost from $30, and the port synchronisers, from $12 (1000).

Integrated Device Technology; www.idt.com