| 摘要 |
PURPOSE:To surely detect the fault of a receiver by comparing the difference between the receiving field outputs of two receivers with the difference between the space transmission losses of a TTR antenna and two receiving antennas which are previously obtained. CONSTITUTION:The test radio waves are received by receivers 3 and 5 via receiving antennas 4 and 6 for base station. Then the radio waves of either one of both receivers are supplied to a differential amplifier 7 with those of the other receiver supplied to a selective switch 11 respectively. The working of the amplifier 7 is controlled by a control signal 14 sent from a test transmitter/receiver TTR1. When a test is carried out by the TTR1, the amplifier 7 goes to active and the difference between the receiving field outputs is amplified and supplied to a comparator 8. At the same time, the voltage corresponding previously to the difference between space transmission losses is produced and supplied to the other side of the comparator 8 to be compared with said difference of receiving field outputs. Thus the output of the comparator 8 is inverted in case an extraordinarily big difference is produced between the receiving field outputs of both receivers 3 and 5. Then the fault information 10 is outputted to show a fault of the receiver. |
