| 摘要 |
PURPOSE:To prevent a transmission allowed signal from being stopped ineffectively owing to a down signal and to improve the utilization efficiency of an up circuit by enqueuing the transmission of the down signal until the up circuit is put in use and the transmission allowed signal is stopped. CONSTITUTION:A buffer memory 14 is provided and even when the down signal is generated 13 during the transmission of the transmission allowed signal 6, the down signal is stored in the buffer memory 14; and the down signal 7 is read out of the buffer memory 14 by a signal selecting circuit 11 when the up circuit is put in use, and then repeated to the output part 12 of a transmitter. Thus, the down signal 7 is transmitted only when the up circuit is in used and the transmission allowed signal 6 is stopped to prevent the transmission allowed signal 6 from being stopped ineffectively owing to the down signal and also to improve the utilization efficiency of the up circuit. |
