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Distance sensing by IQ domain differentiation of time of flight (TOF) measurements

  • US 8,760,631 B2
  • Filed: 12/28/2010
  • Issued: 06/24/2014
  • Est. Priority Date: 01/27/2010
  • Status: Active Grant
First Claim
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1. A method for use with a system that includes an optical sensor and that is configured to determine at least one of a distance or presence of one or more moving objects relative to the optical sensor, the method comprising:

  • (a) driving a light emitting element with a drive signal to thereby cause a light signal to be emitted;

    (b) producing a sensor signal that is indicative of a portion of the light signal that reflects from one or more objects and is incident on the optical sensor;

    (c) performing quadrature demodulation of the sensor signal to produce in-phase (I) and quadrature phase (Q) signals;

    (d) determining derivatives of the in-phase (I) and quadrature-phase (Q) signals; and

    (e) determining a phase of the derivatives of the in-phase (I) and quadrature-phase (Q) signals.

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