PURPOSE: To simplify the constitution with less number of capacitors and coils constituting filters of a channel converter, in a carrier communication system.

CONSTITUTION: Input signals P1∼P3 applied to modulators M1∼M3 at the transmission side are modulated at with carrier waves C1, C2 and C3, a part of unnecessary components (high-band side) is suppressed at a low-pass filter connected to the post stage, the output of filters F11, F21, F31 is coupled by a coupler H1 and remaining unnecessary components at the low band are suppressed by a high pass filter F4. Cutoff frequencies of filters F4, F11, and F12, F21, and F22, F31 and F32 are 8,516kHz, 9,748kHz, 11,068kHz, and 12,388kHz, respectively. On the other hand, a transmission signal having the band of 8,516∼12,388kHz at the reception side is distributed by a distributor H2 and supplied to low-pass filters F12, F22, F32, and frequency components at high band are suppressed for 9,748kHz for F12, 11,068kHz for F22 and 12,388kHz for F32 and connected to modulators M4∼M6 for demodulation. Thus, a channel converter can be formed without using band pass filters of complicated constitution.