| 摘要 |
PURPOSE:To solve deterioration in transmission characteristics by eliminating the need for a repeating coil by interposing a space-division switch of a low-dielectric- strength semiconductor switch between a hybrid and modem. CONSTITUTION:Space-division switch S2 is interposed between hybrid HYB and modem circut CODEC. Sound information from subscriber SUB is inputted to hybrid HYB, where two-wire/four-wire conversion is done. With switches S0-S3, and S0'-S3' all ON, the sound is transferred via the secondary-side route of the secondary side, of the hybrid, S0, S1, COD, earth, balancing network BON, S1', S0, and the secondary side of the hybrid. Then, it also flows via the route of the secondary side of the hybrid. S2, S3, and secondary side of the hybrid. When the conditions of hybrid HYB are satisfied, no current flows through the balancing network and the sound is all consumed by a modulation circuit and terminating resistance in a demodulation circuit. A signal from demodulation circuit DEC is also supplied to a subscriber via the route of DEC output, S3', S2', the secondary side of the hybrid, S2, S3, BON, and DEC. |
