PURPOSE: To improve the ratio of erroneous reception of a transmission signal, by recognizing the transmission quality of a transmission line by a receiver by counting the discrepancy of bits (the number of discrepancy of decoding signals of each node) between diversity nodes, and deleting a reception signal automatically corresponding to the quality, when a digital signal is transmitted.

CONSTITUTION: It is assumed that time diversity is considered as the diversity and the number of nodes N is set at N=2. The signal transmitted from a transmitter is received at the reception antenna 1 of the receiver, and is demodulated at a reception circuit 2. The demodulation signal 7 and a reception level signal 8 at that time are inputted to a time diversity decoding circuit 3. The decoding circuit 3 outputs the decoding signal 9 obtained by selecting the signal having a node of high reception level and a comparison signal 10 obtained by selecting the signal having a node of low reveption level. A comparison and decision circuit 4 counts the number of discrepancy of the decoding signal 9 and the comparison signal 10, and decides whether the demodulation signal should be received or not, and outputs a decision signal 11. The decision signal 11 is inputted to a switching circuit 5. The switching circuit 5 performs the ON/OFF control of the decoding signal 9 corresponding to the decision signal 11. The output of the switching circuit 5 is sent from a terminal 6.