JPS611945B

PURPOSE:To extend the communication distance, by providing band pass filters having different pass frequencies in a pair of amplifiers constituting a two-way repeater to not only prevent frequencies from coming round to respective amplifiers but also improving the gain of amplifiers. CONSTITUTION:When an input signal of a frequency fc comes from a left leakage coaxial cable 10, this frequency is inputted to a mixer MIX1 through a band pass filter BPF1 to obtain frequencies fc+ or -fL as the output. Frequencies fc+ or -fL is permitted to pass through a BPF2 and is sent to an amplifier AMP1 and has only a gain G 1 amplified and is sent to a mixer MIX2 through a PD2. Frequencies (fc-fL)+ or -fL are obtained in the output of the MIX2, and only the frequency fc is selected by a BPF4 and is sent to a right leakage coaxial cable 20. When the input signal of the frequency fc comes from the right leakage coaxial cable 20, the same operation is performed with the exception that the frequency passes through another amplifier AMP2 and band pass filter BPF3.