| 摘要 |
<p>PURPOSE:To form a signal conversion circuit with satisfactory suppression performance of the equiphase noise by providing a means which prevents DC components from DC supply in a two-line/four-line conversion transformer circuit, and a means which suppresses the noise from a telephone-set terminal. CONSTITUTION:Terminals (a) and (b) of a telephone-set terminal are connected to terminals (d) and (e) of a two-line/four-line conversion transformer circuit 9 respectively through capacitors C1 and C2. Terminals (f) and (g) of a DC supply circuit 8 are connected to the terminals (a) and (b) respectively. DC components from the circuit 8 for the circuit 9 are prevented by the capacitors C1 and C2, and the noise from the telephone-set terminal is suppressed. The equiphase noise is eliminated by a two-line/four-line transformer 10 inside the circuit 9. Thus, a signal conversion circuit with satisfactory suppression performance of the same phase noise can be formed.</p> |
