| 摘要 |
<p>PURPOSE:To carry out accurate measurement regardless of scattering light by detecting and holding the peak value of a PAM signal when one PAM signal arrives within a specific time and detecting and holding the peak value of the second signal when two PAM signals arrive within the specific time. CONSTITUTION:The first and second peak detection circuits 1, 2 shape a PAM signal 01 in a delay circuit 3 and are reset by the first and second reset signals 41, 42 obtained in a reset circuit 4 to which a delay pulse 31 delayed by the time corresponding to the repeating cycle thereof and the signal 101 are inputted. In the case only of reflected light, the peak value of the signal 41 is detected but, in such a case that there is scattering light, the circuit 1 is reset by the next reflected light. The signal 42 prevents the detection of the first signal 01 by circuit 2 and, in the case only of reflected light, the peak value of the signal 42 is not detected and, only both when the scattering light and reflected light arrive, the peak value of the reflected light is detected. Thereafter, the outputs 11, 21 of the circuits 1, 2 are superposed by an adder circuit 5 and output 61 is obtained in a sample hold circuit 6. By this method, accurate measurement can be carried out regardless of scattering light.</p> |
