Phase-lock loop-based clocking system, methods and apparatus
AssigneeLightLab Imaging, Inc.
InventorJoseph M. Schmitt
Life of this patent
Estimating the term…
Abstract
In part, the invention relates to an optical coherence tomography system that includes one or more phased-locked loop circuits. In one embodiment, the phased-locked loop circuit includes a phase detector, a loop filter, and a voltage controlled oscillator wherein the phased-locked loop circuit is configured to generate a sample clock. The optical coherence tomography system can include an analog to digital converter having a sample clock input, an interferometric signal input, and a sample data output, the analog to digital converter configured to receive the sample clock and sample OCT data in response thereto. In one embodiment, the phased-locked loop circuit is configured to lock on a first signal in less than or equal to about 1 microseconds.
Claims20
An optical coherence tomography system comprising:
- a control system comprising
- a zero-crossing detector having a first input and a first output, the first input configured to receive a first input signal;
- and
- a first phased-locked loop circuit having a second input and a second output wherein the second input is in electrical communication with the first output, the circuit comprising:
- a phase detector in electrical communication with the second input,
- a loop filter in electrical communication with the phase detector, the loop filter comprising a reference signal input configured to receive a reference control signal, and
- a voltage controlled oscillator in electrical communication with the loop filter and the second output, the phase-locked loop circuit configured to generate a sample clock;
- and
- an analog to digital converter having a sample clock input, an interferometric signal input, and a sample data output, the analog to digital converter configured to receive the sample clock and sample OCT data in response thereto.
An optical coherence tomography system comprising:
- a control system comprising:
- a zero-crossing detector having a first input and a first output, the first input configured to receive a first input signal;
- and
- a phased-locked loop circuit having a second input and a second output wherein the second input is in electrical communication with the first output, the circuit comprising
- a phase detector in electrical communication with the second input, the phase detector comprising a reference input and a phase error signal output,
- a phase error compensator in electrical communication with the phase error signal output and comprising a phase error compensator output and a sweep trigger signal input, and
- a voltage controlled oscillator in electrical communication with the phase error compensator output and the second output, the voltage controlled oscillator having a VCO frequency, the phase-locked loop circuit configured to generate a sample clock, and
- an analog to digital converter having a sample clock input, an interferometric signal input, and a sample data output, the analog to digital converter configured to receive the sample clock and sample OCT data in response thereto.
A method of clocking an analog to digital converter configured to sample optical coherence data from a main interferometer in an optical coherence tomography system comprising:
- receiving a first clock signal having a first phase at a first input to a phase-locked loop;
- locking on the first clock signal within a first time period;
- detecting the first phase of the first clock signal;
- frequency multiplying the first clock signal or a signal derived therefrom by N using an oscillator to generate a sample clock;
- and
- clocking an analog to digital converter in electrical communication with a photoreceiver in optical communication with an interferometer configured to collect OCT data.
Dependencies are inferred from the claim text.