| 摘要 |
The invention refers to single-ended test of a loop (2, 3) with the aid of a transceiver (1), wherein an input impedance (Zin(f)) of the loop is generated. The transceiver (1) has a digital part (41), a codec (42) and an analog part (43) and is connected to the loop. With the aid of a transmitted and a reflected braodband signal (vin, vout) an echo transfer function Hecho(f) = V(f)out/Vin (f) is generated, which also can be expressed as formula (I). Here Zho(f), Zhyb(f) and Hepsilon(f) are model values for the transceiver (1). IN a calibration process a test transceiver, with the same type of hardware as the transceiver (1), is connected to known impedances, replacing the loop (2, 3). Hecho(f) = V( f)out/Vin(f) is generated for the known impedances and th emodel values are generanted and are stored in a memory (11) in the transceiver (1). The stored model values are then used when the input impedance (Zin(f)) for the loop (2, 3) is generated after a measurement of the broadband signal (V in, Vout) is performed.
|
