| 摘要 |
PURPOSE:To display automatically a cursor line on a CRT screen, by storing picture information of the cursor line, where the peak value of a completely reflected waveform is the base line, together with picture information of the reflected waveform of a cable to be measured in a picture memory corresponding to the CRT screen. CONSTITUTION:When the contact of a switching circuit 14 is connected to a contact (a), the reflected waveform from a cable to be measured is converted in an A/D converter 15, and the digitized reflected waveform from the cable to be measured is sent into a picture memory 16. When the contact of the switching circuit 14 is connected to a contact (b), a peak value Vp of the completely reflected waveform detected by a peak detecting circuit 11 is converted in the A/D converter 15 and is stored in a prescribed address of the picture memory 16 and becomes a cursor line 7 on a CRT screen 1. When the contact of the switching circuit 14 is connected to a contact (c), a level value Vo-Vp outputted from a subtracting circuit 13 is stored in the picture memory 16 through the A/D converter 15 to describe a cursor line 8. As the result, a cursor line corresponding to the peak value of the completely reflected waveform, namely, 0dB is obtained automatically. |
