| 摘要 |
PURPOSE:To simplify the constitution of the transmission output control loop of a radio equipment by converting the leaked surface wave which has not been effectively used into an electric signal and performing a monitor output of the signal. CONSTITUTION:An electric signal 4 is inputted from a terminal 1 and it is injected to electric/acoustic transducers of 7-1, 7-2 and 7-3. The injected electric signal is converted into a surface wave 5-1, the signal is propagated to acoustic/ electric transducers of surface waves 8-1, 8-2, 8-3 and 8-4, the signal is returned to an electric signal 10 and it is taken out from an output terminal 2. At this time, part of the surface wave passes through the surface waves 8-1 and 8-4 and becomes a leaked surf ace wave of 6-1. This leaked surface wave 6-1 is converted into an electric signal 11 by acoustic/electric transducers 9-1 and 9-2 with reflectors and is taken out from a monitor terminal 3. The electric signal 11 is returned as the output of a filter 23 with output monitor to an output control circuit 20, and the output of an amplifier 18 is controlled to be within a specified value. Even in such a constitution that the number of the elements of a surface wave filter is increased and video is connected, this action is absolutely the same. |
