| 摘要 |
PURPOSE:To make it possible to measure the quantity of extinction with a high ascuracy by supplying alternately signal light and reference light through a zero signal and completely removing the zero-drift part using a DC bias voltage. CONSTITUTION:The output light rays from a laser light source 1 successively pass through two rotating reference cells 8 and 8' and circular holes 9 and 9', respectively, and injected in a photodetector 6. Accordingly, in the output signal of the detector 5, a signal light signal and a reference light signal are alternately produced through a zero signal, and supplied to a signal processing circuit. In the signal processing circuit, a DC bias voltage is once superimposed on these signals, and a signal of a waveform formed by placing the described signals on a part formed by subtracting a zero-drift part from the DC bias part is produced. Further, a circuit making it possible to subtract the DC bias part from the signal is constituted. By this organization, the establishment of the zero point indispensable for the measurement is carried out with a high accuracy, and the improvement in the accuracy in the measurement of the quantity of extinction can be attempted. |
