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Obstacle detection sensor using synchronous detection

  • US 20020190195A1
  • Filed: 08/05/2002
  • Published: 12/19/2002
  • Est. Priority Date: 12/15/2000
  • Status: Active Grant
First Claim
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1. A method of detecting an optical signal in the presence of ambient light, the method comprising the steps of:

  • receiving an optical signal having a first frequency and a first phase in the presence of an ambient light signal;

    amplifying said received optical signal and said ambient light signal;

    synchronously detecting said received optical signal and ambient light signal to provide a synchronously detected signal;

    subtracting said synchronously detected signal from a predetermined offset voltage to provide a subtracted signal;

    integrating said subtracted signal over a predetermined period of time to provide an integrated signal; and

    detecting a change in said integrated signal indicative of a change in said optical signal.

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