| 摘要 |
The invention relates to a device for looping a radio-frequency test signal transmitted by a transmitter section in a full duplex type transceiver to a receiver section for testing the transceiver. The device of the invention comprises mixing means (23, 28) for shifting the test signal from the transmitting frequency to the receiving frequency. Interference caused in the normal reception of the receiver by the test signal is prevented by switching means (31) positioned in a device output. The switching means separate the test signal from the input of the receiver between the test intervals. The device further comprises means (D1, 35, 36, 38) for supervising the operation of the switching means (31) by monitoring the signal level in the device output. |
