| 摘要 |
PROBLEM TO BE SOLVED: To control electromagnetic interference with a simple configuration by changing reception sensitivity of each radio terminal so as to configure an area of a radio communication system so that a radio terminal detects only a radio communication signal of a radio base station to which the radio terminal belongs. SOLUTION: An automatic gain control(AGC) circuit of a radio terminal converts a communication signal into a prescribed amplitude when the amplitude of the communication signal is within a range (minimum value VL - maximum value VH) and provides an output to a demodulation circuit of a next stage. The reception sensitivity is fluctuated by intentionally adjusting the minimum value VL of the automatic gain control circuit. That is, since a minimum detection level is adjusted to a decreased detection level A that is more than a reception level of an interference wave, interference noise is converted into a white noise and the noise can be processed as a same noise independently of its kind, that is, a thermal noise independently of a desired wave. Thus, the noise immunity equal to any kind of interference noise is obtained. |
