| 摘要 |
PURPOSE:To attain transmission and reception at the same time by eliminating a reception signal mixed in a 4-wire transmission signal with subtraction so as to improve the ringing elimination capability of the line. CONSTITUTION:A ringing prevention device consists of a resistance matrix circuit 1, a subtraction circuit 2, an equalizing circuit 3 and a buffer circuit 4. A transmission signal V inputted from a 2-wire transmission/reception terminal 2W is mixed with a signal being a reception signal R inputted from a 4-wire reception terminal through the resistance matrix circuit 1 while being branched by the buffer circuit 4. The subtraction circuit 2 subtracts the other branched reception signal through the equalizing circuit 3 from the mixed transmission/ reception signal to eliminate the reception signal from the transmission/reception signal. As a result, only the transmission signal at the transmission/reception terminal 2W is obtained as an output at the 4-wire transmission terminal 4W-S.
|
