| 摘要 |
In order to detect a failure of an amplifier or a filter of a local signal generating section of a receiver or a synthesizer of a radio communication unit, e.g. a radio base station unit accurately in real time, a local signal used for frequency conversion is inputted to the input of the amplifier or filter, only the local signal component is taken out of the output of the amplifier or filter and detected, and the detected voltage is compared with a failure detection level, thus judging whether the amplifier or filter is normal or not. A failure can be detected more accurately by varying the failure detection level depending on the variation of temperature or local signal frequency (channel frequency). |
