Method and device for light signal reception
View Patent ↗Method and device for light signal reception. This device can selectively execute a comparison mode or a gain mode. In the device, a transmitter transmits a light beam to a target. A receiver receives the light beam reflected from the target and outputs a corresponding received signal. In the comparison mode, it is determined whether a pulse in the received signal is higher than a reference voltage level. When the pulse is higher the reference voltage level, the pulse is outputted. The gain mode is executed and the received signal is amplified and output when no pulse is higher than the reference voltage level in the received signal. The method and device of the present invention can be applied to range finders, the comparison mode is executed during short-distance measurement and the gain mode is executed during long-distance measurement thereby measuring the target distance from several meters to a thousand meters.
1. 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.
2. The method as claimed in claim 1 , wherein the pulses smaller than the reference voltage level are eliminated by a comparison circuit in step (C).
3. The method as claimed in claim 2 , wherein the second received signal is amplified by a gain circuit in step (F).
4. The method as claimed in claim 3 , wherein the gain circuit amplifies the second received signal non-linearly.
5. The method as claimed in claim 3 , wherein the gain circuit has a feedback voltage level which is feedback from an output terminal of the gain circuit to an input terminal of the gain circuit.
6. The method as claimed in claim 3 , further comprising a step of connecting a channel selection circuit to the comparison circuit or the gain circuit selectively.
7. A device, comprising:
a transmitter transmitting a light beam to a target;
a receiver receiving the light beam reflected from the target and outputting a corresponding received signal;
a comparison circuit having a reference voltage level, and receiving the received signal to determine whether a pulse is higher than the reference voltage level, in the received signal;
a gain circuit receiving the received signal from the receiver to amplify and output a corresponding amplified signal;
a processor receiving and processing the pulse or the amplified signal to determine the distance between the target and a ranger finder, and
a channel selection circuit selectively outputting one of the pulse from the comparison circuit and the amplified signal from the gain circuit to the processor according to a channel selection signal.
8. The device as claimed in claim 7 , wherein the gain circuit has a feedback voltage level which is feedback from an output terminal of the gain circuit to an input terminal of the gain circuit.