Patent ID: 7193689

Claim:
A method for light signal reception, comprising the steps of: (A) transmitting a light beam to a target; (B) receiving the light beam reflected from the target and outputting a first received signal, wherein the received signal has at least one pulse; (C) eliminating pulses smaller than a reference voltage level in the first received signal and determining whether a pulse is higher than the reference voltage level in the first received signal without processing by a gain circuit; (D) outputting the pulse to a processor to execute operational processes when the pulse in the first received signal is higher than the reference voltage level; (E) repeating the steps (A) and (B) to obtain a second received signal when, in the first received signal, no pulse is higher than the reference voltage level; and (F) amplifying the second received signal and outputting to the processor to determine the distance between the target and a ranger finder according to the pulse or the amplified second received signal.