Amir I Lahat

US Patent:

7289538, Oct 30, 2007

Filed:

Aug 14, 2002

Appl. No.:

10/218284

Inventors:

On Paradise - Tel Aviv, IL
Amir Lahat - Sunnyvale CA, US
Zvika Bronstein - Ramat Efal, IL
Pavel Hardak - Lod, IL
Gila Klein - Rosh Ha'ain, IL

Assignee:

Atrica Israel Ltd. - Herzelia

International Classification:

H04J 1/02

US Classification:

370497, 370518

Abstract:

A clock reconstruction mechanism for synchronous TDM communications traffic transported over asynchronous networks such as Ethernet networks. The invention is applicable to edge switches in Metropolitan Area Networks (MANs) that transport legacy TDM traffic using a Circuit Emulation Services (CES) module whereby TDM traffic is encapsulated and transported across the Ethernet network where it is de-encapsulated and clocked out to the destination. The mechanism encapsulates the input TDM data stream into Ethernet packets and inserts a network timestamp within the packet. At the destination CES, a local timestamp is generated for each received packet as it is received. The network timestamp is extracted and input along with the local timestamp to a Digital Time Locked Loop (DTLL) which is operative to accurately reconstruct the original transmit TDM clock. The filter in the DTLL performs a Least Squares Regression (LSR) algorithm and Infinite Impulse Response (IIR) filter algorithm to generate a clock control signal for adjusting the clock generated.

US Patent:

7613212, Nov 3, 2009

Filed:

Jun 10, 2003

Appl. No.:

10/459217

Inventors:

Yaron Raz - Ramot Meir, IL
Pavel Hardak - Lod, IL
Amir Lahat - Cupertino CA, US
Alex Arnon - Tel Aviv, IL
Gila Klein - Rosh Ha'ain, IL

Assignee:

Atrica Israel Ltd. - Hod Hasharon

International Classification:

H04J 3/06

US Classification:

370510, 370512

Abstract:

A centralized clock distribution mechanism for synchronous TDM communications traffic transported over asynchronous networks such as Ethernet networks. The centralized clocking mechanism of the present invention distributes a high accuracy central clock source to a plurality of CES modules over an Ethernet network. Clock synchronization information based on a high quality clock reference source is distributed to circuit emulation service (CES) modules in the network. CES modules receive the clock synchronization information and use it to reconstruct a local clock. A plurality of clock distributors provide clock redundancy whereby each CES module selects the best clock source to use in reconstructing the local clock.