| 摘要 |
PROBLEM TO BE SOLVED: To provide a receiving circuit in which the disturbing signal level exceeds a reference line of an IS-95 and a total C/N of the received signal level has satisfactory performance. SOLUTION: This receiving circuit includes an RF amplifier 1 which amplifiers the variable gain of a received signal, a bypass circuit 2 which is connected in parallel to the amplifier 1, and a control switching part 10, which performs the switching between the gain state of the amplifier 1 and the connection state of the circuit 2, in response to the received signal level. The part 10 sets the amplifier 1 in an automatic gain amplification state, and the circuit 2 in a first operation state where the circuit 2 is set in a non-connected state, when the received signal level rises as the time elapses in a 1st range where the signal level is minimized. Then the part 10 sets the amplifier 1 in a non- operating state and the circuit 2 in a 2nd operation state where the circuit 2 is set in a connection state, when the received signal level is shifted to a second range larger than a first range. When the received signal level decreases as the time elapses and then lowers down to an intermediate level between the first and second ranges, the part 10 switches the amplifier 1 and the circuit 2 to the first operating state from the second operation state respectively. |
