Abstract:
A compensating current is applied at one or more points in a signal processing path to compensate for one or both of a dark or offset current present in an input signal. In certain implementations, the dark or offset current is present in a signal generated by a photomultiplier device. The dark or offset current may be monitored in an output of the signal processing path and, the monitoring being used to determine how much compensation is needed in the signal processing path and to allocate where in the signal processing path the compensation current will be applied.
Abstract:
In order to detect a passage timing of a light beam and to suppress cost, a light beam detection circuit (2) includes a detection signal generation section (34) configured to receive a light beam for scanning of a scanning target (101A) with one optical sensor (10), and generate a detection signal corresponding to an amount of received light; a reference signal output section (44) configured to output a reference signal that is in proportion to a light-amount control signal of a light-emission element (LD1) that emits the light beam; and a synchronizing signal generation section (35) configured to compare a detection signal generated by the detection signal generation section (34) with a reference signal output from the reference signal output section (44) to generate a synchronizing signal to determine a position to start scanning of the scanning target (101A) with the light beam.
Abstract:
A system and method with AC coupling that reserves photodiode bandwidth in a biased configuration, allows optimal transimpedance amplifier performance, retains DC signal measurement capability, and does not introduce noise into the balanced detection signal.
Abstract:
A compensating current is applied at one or more points in a signal processing path to compensate for one or both of a dark or offset current present in an input signal. In certain implementations, the dark or offset current is present in a signal generated by a photomultiplier device. The dark or offset current may be monitored in an output of the signal processing path and, the monitoring being used to determine how much compensation is needed in the signal processing path and to allocate where in the signal processing path the compensation current will be applied.
Abstract:
In order to detect a passage timing of a light beam and to suppress cost, a light beam detection circuit (2) includes a detection signal generation section (34) configured to receive a light beam for scanning of a scanning target (101A) with one optical sensor (10), and generate a detection signal corresponding to an amount of received light; a reference signal output section (44) configured to output a reference signal that is in proportion to a light-amount control signal of a light-emission element (LD1) that emits the light beam; and a synchronizing signal generation section (35) configured to compare a detection signal generated by the detection signal generation section (34) with a reference signal output from the reference signal output section (44) to generate a synchronizing signal to determine a position to start scanning of the scanning target (101A) with the light beam.
Abstract:
The objective of the present invention is to quickly and precisely correct the measured value for light reception power to the actual value with few resources, by installing a correction device for a light reception power monitor for signal light in an optical module. The correction device is equipped with a correction table which is referenced when correcting the measured value for the light reception power of signal light, and in this correction table multiple correction values are stored in advance on the basis of the correspondence relationships between multiple reference values and multiple actual values. In the correction table, for segments wherein the change in the actual values with respect to the change in the measured values is small, the interval between the reference values is made smaller and more correction values are stored than for segments wherein the change in the actual values with respect to the change in the measured values is large. When an input value indicating the measured value for the light reception power of the signal light matches a reference value in the correction table, the correction device reads from the correction table the correction value corresponding to the reference value. When an input value does not match a reference value in the correction table, the correction device calculates a correction value in accordance with a prescribed calculation formula on the basis of the input value.
Abstract:
A photodetector control circuit in a photodetector for detecting light from a photodiode using a phototransistor and controls drive of the photodiode and detection of a current of the phototransistor has a received light amount detecting unit that detects a detection current, which flows through the phototransistor in accordance with a received light amount, by converting the detection current into a detection voltage, and compares the detection voltage with a reference voltage detected during reception of a reference light amount, to thereby detect a change in the received light amount, a diode current control unit for controlling a diode current that is caused to flow through the photodiode, and a control unit that detects a temperature based on a forward drop voltage of the photodiode and estimates a current change rate of the phototransistor based on the detected temperature.