Patent ID: 7283214

Claim:
A laser range finder, comprising: a laser; a photosensitive element providing an output signal in response to illumination and positioned to measure self-mixing induced intensity variations in a beam emitted by the laser; a phased locked loop (PLL) in electrical communication with the photosensitive element, the PLL receiving the output signal of the photosensitive element; a frequency counter receiving output from the PLL; at least one signal preconditioning element positioned between the photosensitive element and the PLL, the at least one signal preconditioning element pre-conditioning the photosensitive element output signal prior to receipt of the photosensitive element output signal by the PLL; and a bias current generator providing bias current to the laser, and wherein the bias current generator provides a bias current modulated with a triangular wave, and the at least one signal preconditioning element removes bias current modulation from the photosensitive element output signal prior to the PLL receiving the photosensitive element output signal.