| 摘要 |
The invention relates to a line driver circuit, comprising a driver stage (11) and a transformer provided with a primary and secondary windings (12a, 12b) in such a way that output terminals of the driver stage (11) are connected to terminals of the primary winding (12a) of the transformer and terminals of the secondary winding (12b) of the transformer are connected to a transmission line (13), at least one matching resistor (Rm) being connected to the terminals of the primary winding of the line driver circuit. To provide a line driver circuit having a good return loss and a low power consumption, it comprises driver means (51 to 53; 71, 72; 81, Q1, Q2) connected to said at least one matching resistor and responsive to an output signal of the driver stage (11) for disconnecting the matching resistor (Rm; Rm1, Rm2) for the time of pulses transmitted by the driver stage. |
