FREQUENCY DIVERSITY COMMUNICATION DEVICE

PURPOSE:To set a system to be impervious to interference and shock due to external noises by providing two kinds of BPF, judging the normality/ abnormality of input at every prescribed time and switching BPF to different BPF when it is judged to be not normal. CONSTITUTION:A transmission system 10 transmits the two signals of frequencies f1 and f2 modulated by the same base band signal D. BPF21A tuned to the frequency f1 and BPF 21B tuned to the frequency f2 are provided for a reception system 20. A data processing part 30 judges whether the signal inputted at every prescribed time is a regular signal or not. When it is judged to be an abnormal signal, a switch change-over command is transmitted to change- over switches 22A and 22B. The switches 22A and 22B select BPF 21B rather than BPF 21A by the switch change-over command. Only the reception wave of the frequency f2 passes through BPF 21B and it is inputted to a mixer 24. Since BPF is selected until normal output can be obtained, the system can be set to be impervious to interference and shock on account of external noise.