Phase rotation circuit for eye scope measurements
AssigneeKandou Labs, S.A.
InventorArmin Tajalli
Life of this patent
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Abstract
Methods and systems are described for generating, with a local oscillator and an adjustable phase interpolator, a data-sampling clock and a variable-phase-offset eye-measurement clock, forming a received data signal using a multi-input comparator, generating, using a data slicer and the data sampling clock, a receive sample of the received data signal, and generating, using at least one eye slicer and the variable-phase-offset eye-measurement clock, a plurality of eye characteristic measurements by adjusting a sampling threshold of the at least one eye slicer and a phase offset of the variable-phase-offset eye-measurement clock.
Claims20
A method comprising:
- selecting a local oscillator output as a data-sampling clock for a data sampler and a phase interpolator output as a variable-phase-offset eye-measurement clock for an eye sampler and obtaining a first phase interpolator code that aligns a sampling instant of the eye sampler to an edge of an eye with respect to a data sampling instant of the data sampler;
- selecting the phase interpolator output as the data-sampling clock for the data sampler and the local oscillator output as the variable-phase-offset eye-measurement clock for the eye sampler and obtaining a second phase interpolator code that aligns the sampling instant of the eye sampler to the edge of the eye with respect to the data sampling instant of the data sampler;
- and
- outputting a phase interpolator delay value by combining the first and second phase interpolator codes.
An apparatus comprising:
- a local oscillator configured to generate a local oscillator output;
- a phase interpolator configured to generate a phase interpolator output based on the local oscillator output, the phase interpolator having a phase interpolator delay value determined from first and second phase interpolator codes;
- a selection circuit configured to:
- select the local oscillator output as a data-sampling clock for a data sampler and the phase interpolator output as a variable-phase-offset eye-measurement clock for an eye sampler to obtain the first phase interpolator code that aligns a sampling instant of the eye sampler to an edge of an eye with respect to a data sampling instant of the data sampler;
- and
- select the phase interpolator output as the data-sampling clock for the data sampler and the local oscillator output as the variable-phase-offset eye-measurement clock for the eye sampler to obtain the second phase interpolator code that aligns the sampling instant of the eye sampler to the edge of the eye with respect to the data sampling instant of the data sampler.
Dependencies are inferred from the claim text.