Phase Locked Loop with Optimal State Feedback Controller
AssigneeZarlink Semiconductor Inc.
InventorKamran RAHBAR
Life of this patent
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Abstract
In a method of recovering timing information over a packet network at a local receiver, timing information is received at intervals timing from a remote source and compared with a locally generated clock signal to generate an input signal y(k) subject to noise representative of the phase difference between the source clock signal and the local receiver clock signal. The input signal is applied to a state feedback controller, preferably including a Kalman filter, to generate a control signal with reduced noise. The control signal is used to control an oscillator in a way so as to reduce the phase difference and generate a slave clock.
Claims19
A method of recovering timing information over a packet network at a local receiver, comprising:
- receiving at intervals timing information about a remote source clock signal;
- generating a local clock signal with a controlled oscillator;
- comparing the local timing signal with the received timing information to generate a noisy input signal y(k) representative of the phase difference between the source clock signal and the local receiver clock signal;
- applying said input signal y(k) to a state feedback controller to generate a control signal with reduced noise;
- and
- controlling said controlled oscillator with said control signal to reduce said phase difference and generate a slave clock signal from said remote clock signal.
A phase locked loop for recovering timing information over a packet network at a local receiver, comprising:
- a controlled oscillator for generating a slave signal in response to a control signal;
- a phase comparator for comparing timing information received from a remote source with the slave signal to generate a noisy input signal;
- and
- a state feedback controller for generating a cleaned control signal from the noisy input signal.
Timing recovery apparatus for recovering timing information over a packet network at a local receiver, comprising:
- an input for receiving remote time stamped packets from a remote source over the packet network;
- a local controlled oscillator for generating a slave clock in response to a cleaned control signal;
- a generator for generating local time stamped packets based on said slave clock and coinciding with the arrival of time stamped packets from the source;
- a comparator for comparing said time stamped packets received from the source with the locally generated time stamped packets to derive said input signal;
- and
- a state feedback controller for generating said cleaned control signal from said input signal.
Dependencies are inferred from the claim text.