| 摘要 |
<p>PURPOSE: To obtain a highly accurate voltage measuring apparatus. CONSTITUTION: A processing section 600 notifies a designated number N (=1,2,...) to a drive section 300. The drive section 300 delivers a drive signal of frequency f0 to a device being measured and a modulation signal of frequency f0 +Δf to a light source 110. The light source 110 outputs an intensity modulated light which is passed through an optical system, including a PBS 120, a wavelength plate 130, etc., to an E-O probe 200 where the intensity modulated light is affected by a periodic voltage waveform of basic frequency 1/f0 generated at a part to be measured and modulated before being outputted therefrom. The modulated optical signal is fed to the PBS 120 where the polarizing direction is selected and then it is fed to a photodetector 510 and subjected to heterodyne detection. Based on an optical detection signal thus obtained, the processing section 600 reproduces the waveform of voltage signal generated at the part to be measured according to Fourier Transform and displays the reproduced waveform.</p> |
