摘要 |
PURPOSE:To facilitate the measurement of the phase difference between the commercial power waveform and the video signal waveform of a power synchro nizing camera which uses the commercial frequency as the vertical synchronizing frequency. CONSTITUTION:The commercial power waveform CW to be observed by an oscilloscope 10 is defined as the waveform of a secondary coil 13b of an insulated transformer 13. Therefore a ground input terminal 11 of the oscilloscope 10 is never fluctuated by the commercial frequency and the power hum component is never mixed into a vertical synchronizing signal waveform. As a result, the synchronization of a video signal waveform VW is easily secured through the oscilloscope 10 and an easy-to-see waveform VW is obtained. Then the phases of the waveform CW and the vertical synchronizing signal waveform contained in the waveform VW can be easily measured. |