| 摘要 |
PURPOSE:To eliminate pulselike noise and improve accuracy of detection by detecting a rotating laser beam with plural photodetectors, removing error signals through a phase synchronizing loop and digitally processing the plural signals. CONSTITUTION:When a rotating laser beam L enters a solar battery SC, negative pulses are produced at the point (a) through a transistor 22, and the output from the output terminal 24 of an inverter 23 is applied to the input terminal 31 of a phase synchronizing loop 30. The pulse signal thereof is compared with the phase of the oscillation signal from a voltage control oscillator 35 in a phase comparator 33 via an amplifier 32. The deviation signal thereof is applied via a loop filter 34 to the voltage control oscillator 35 whereby the phase difference is reduced. The output of the loop 34 outputs a digital signal through a source follower 36, and a comparator 37. The outputs of four pieces of such solar batteries are processed, whereby the incidence position of the beam is detected strongly against noise and with good accuracy. |
