| 摘要 |
PURPOSE: A noise removing device of a printed circuit board test is provided which eliminates all of high-frequency and low-frequency noises without affecting analog test. CONSTITUTION: A printed circuit board tester connects a plurality of signal lines to a printed circuit board to test the board. Diodes(D1-Dn) and resistors(R1-Rn) are connected to the signal lines connecting the printed circuit board tester and the printed circuit board in parallel, and one end of each of the resistors is connected to the ground through a relay(RY). The relay is turned on in the case of digital test to allow the resistors connected to the signal lines to be connected to the ground. Thus, the diodes operate in forward direction so that the signal lines maintain low impedance state. The relay is turned off in the case of analog test to make the resistors be separated from the ground to allow the diodes to operates in reverse-direction. As a result, the signal lines are electrically isolated from one another.
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