Broadcom Corporation

James P Cavallo

Tak Kwan Lee

Jeffrey Scott Putnam

Thomas J Kolze

Bruce Joseph Currivan

Jonathan S Min

Loke Kun Tan

Fang Lu

Kevin Lee Miller

Thuji Simon Lin

Ravi Bhaskaran

Gopal Triplicane Venkatesan

Hsin-An Liu

A clock signal regeneration system and method to adjust the phase of a frequency-locked clock signal is provided. The system includes a numerically controlled oscillator, a clock source, and an adder. In one embodiment, additional components are included in the system to ensure that underflow or overflow of the numerically controlled oscillator is prevented. In another embodiment, additional components are included to ensure that output pulses from the numerically controlled oscillator do not occur within a minimum time interval. The method includes deriving a phase adjustment factor, adding the phase adjustment factor to a frequency control word, providing the modified frequency control word to a numerically controlled oscillator and generating a phase shifted, frequency-locked output signal.

System and method for adjusting the phase of a frequency-locked clock

All digital reference frequency locking. An all digital approach is provided for operation within one or more CMs within a cable modem communication system to lock the upstream of the one or more CMs to the downstream symbol clock provided from a CMTS. The locking of the CM's upstream may be performed using one of at least three different functions: (1) Locking the upstream symbol clock phase to the downstream symbol clock phase, (2) Locking the downstream symbol clock phase to the headend reference clock phase (typically 10.24 MHz or integer multiple thereof), and (3) Locking the upstream carrier frequency to the downstream symbol clock frequency. The all-digital techniques for supporting all digital reference frequency locking functionality provide high performance to support S-CDMA and other synchronous modulation techniques.

All digital reference frequency locking

Growing community of inventors

Laguna Niguel, CA, United States of America

James P Cavallo