| 摘要 |
<p>PURPOSE:To measure a current or voltage without requiring any high-precision equipment by detecting the peak timing of the output of a photodetecting element and performing signal processing, and imposing pulse width modulation upon the measurement signal and thus generating a pulse-width modulated wave. CONSTITUTION:A polarizer 2 and an analyzer 5 are arranged between a light emitting 1 and a light receiving element 6 so that their planes of polarization are parallel (or perpendicular) to each other, and the 1st and the 2nd optical modulating elements (Faraday element) 3 and 4 are arranged in series between the polarizer 2 and analyzer 5. Then, the measured signal is modulated optically by the element 3 and a triangular wave or saw-tooth wave carrier signal is modulated optically by the element 4. The peak timing of the output of the light receiving element 6 is detected by a peak detecting circuit 13 and processed by a signal processing circuit 14 to generate the pulse-width modulated wave by imposing pulse width modulation upon the measured signal, and the wave is passed through a demodulating circuit 15 to obtain a voltage signal proportional to the measured signal.</p> |
