| 摘要 |
PROBLEM TO BE SOLVED: To observe precisely an output waveform from a device to be measured having a high output impedance and a low load driving capacity. SOLUTION: This waveform input circuit 10 is equipped with a terminal resistance of a high input impedance receiving an input signal from a transmission line 11, a selection means (relay) 12 for selecting either of the terminal resistance and another terminal resistance, and an input buffer 13 connected when the terminal resistance of the high input impedance is selected by the selection means 12. The circuit 10 is also equipped with a switching means 16 for switching a reference potential of the transmission line 11 to at least two kinds of reference potentials. One reference potential to be switched by the switching means 16 is 'a potential controlled in the same phase as the input signal by an output signal from the input buffer 13 connected when the terminal resistance of the high input impedance is selected by the selection means 12'. COPYRIGHT: (C)2006,JPO&NCIPI
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