| 摘要 |
PURPOSE:To economize the test of a PB signal by processing digitally the PB signal. CONSTITUTION:In applying a subscriber line test, the subscriber circuit 3 of a time division exchange switches a PB telephone set 1 and a subscriber line 2 from the position of an exchange 7 into the position of a subscriber line test device 4. In this state, the test device 4 conducts the DC resistance test and the counter ground unbalance test of the subscriber line 2 and the result is displayed on a display device 6. Further, the test from the PB telephone set 1 to the PB signal is conducted by a PB signal test circuit 5, the PB signal inputted to the test circuit 5 is converted into a digital signal by an A/D converter 11, detected by a digital filtering processing by a digital signal processing processor 12, inputted to a ROM 13 and the result of test is displayed on the display device 6.
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