US 12,425,033 B2 · System and method for remote digital time transfer

Abstract

Methods and systems for synchronizing at least one remote local oscillator with a central local oscillator, comprising receiving a remote local oscillator signal from at least one remote local oscillator and a master local oscillator signal from the central local oscillator and in response determining a round-trip phase measurement of temporal delay variability of the duplex real-time link between the remote station and central station, measuring frequency vs. time of the remote local oscillator signal relative to the master oscillator, adjusting the measured frequency vs. time according to the round-trip phase measurement to remove effects of temporal delay variability over the duplex real-time link telemetry, digitally filtering the measured frequency to remove variations in frequency on timescales<10× the round-trip delay and that are known not to be intrinsically due to the remote local oscillator, generating a phase increment signal from the filtered measured frequency, receiving and adjusting the local oscillator signal according to the phase increment signal and in response generating a derived digital domain clock signal that tracks the master local oscillator signal and converting the derived digital domain clock signal to an ultra-low phase-noise time domain voltage clock signal.

Claims12

Dependent claims

A system for synchronizing at least one remote station with a central station over a duplex real-time link, comprising:

a distributed incoherent clocking module for receiving a remote local oscillator signal from at least one remote station and a master local oscillator signal from the central station and in response to:
determining a round-trip phase measurement of temporal delay variability of the duplex real-time link between the remote station and central station,
measuring frequency vs. time of the remote local oscillator signal relative to the master oscillator signal,
adjusting the measured frequency vs. time according to the round-trip phase measurement to remove effects of temporal delay variability over the duplex real-time link telemetry, and
generating a phase increment signal;
a direct digital synthesizer for receiving and phase adjusting the local oscillator signal according to the phase increment signal and in response generating a derived digital domain clock signal that tracks the master local oscillator signal;
and
a digital to time domain clock converter for converting the derived digital domain clock signal to an ultra-low phase-noise time domain voltage clock signal.

5 more elements

A method of synchronizing at least one remote station with a central station over a duplex real-time link, comprising:

transmitting a remote local oscillator signal from the remote station over the duplex real-time link;
receiving the remote oscillator signal from the duplex real-time link at the central station;
measuring frequency vs. time of the remote local oscillator signal relative to a central oscillator signal at the central station;
determining a round-trip phase measurement of temporal delay variability of the duplex real-time link between the remote station and central station;
adjusting the tracked frequency of the remote local oscillator signal according to the round-trip phase measurement to remove effects of temporal delay variability over the duplex real-time link;
low-pass filtering frequency jitter from the tracked frequency on timescales less than 10× the round-trip delay over the link;
converting the low-pass filtered tracked frequency vs. time measurements to a periodically calculated and applied phase increment signal;
clocking a direct digital synthesizer at remote station with the remote local oscillator signal phase adjusted by the periodically calculated and applied phase increment to generate a derived digital domain clock signal;
and
converting the derived digital domain clock signal to an ultra-low phase-noise time domain voltage clock signal.

7 more elements

Dependencies are inferred from the claim text.

System and method for remote digital time transfer

Life of this patent

System and method for remote digital time transfer

Life of this patent

Abstract

Claims12