| 摘要 |
PURPOSE:To make it unnecessary to use an expensive filter, by taking matching with only an optional channel line, and heightening the input/output impedance with other each channel line, in case of impedance matching of a transmission cable and each channel line. CONSTITUTION:An impedance (hereinafter described as Z) converting circuit 27 between a band pass filter 26 of a slave machine and a coaxial cable 36 is constituted so that its input Z27 is the same as a characteristic Z of the cable 36 in all the frequency bands. A Z converting circuit 31 between a BPF 30 and the cable 36 is constituted as a sufficiently high Z by which its input Z31 can be neglected with respect to the characteristic Z. A converting circuit 35 between a BPF 34 and the cable 36 is constituted as a high Z in the same way. Since a transmitting part 33 has a low output Z, its input Z33 or Z34 becomes a low Z. Z converting circuits 37, 40 and 43 of a master machine are the same as the converting circuits 27, 31 and 35 of the slave machine corresponding to each of them. By constituting in this way, Z23 is equal to Z27, and in the same way, Z24 becomes equal to Z37, and the matching can be taken with the coaxial cable. |
