| US 7,496,150 B2 | ||
| Transmission apparatus with variable impedance matching | ||
| Alberto Canella, Villach (Austria); Christian Jenkner, Velden (Austria); and David Schwingshackl, Villach (Austria) | ||
| Assigned to Infineon Technologies AG, Munich (Germany) | ||
| Filed on Oct. 29, 2004, as Appl. No. 10/977,711. | ||
| Claims priority of application No. 103 54 113 (DE), filed on Nov. 19, 2003. | ||
| Prior Publication US 2005/0114427 A1, May 26, 2005 | ||
| Int. Cl. H04M 7/04 (2006.01) | ||
| U.S. Cl. 375—295 [379/394; 379/398] | 9 Claims |
| 1. Transmission apparatus for transmission of electrical signals between a line driver, which is connected to a transmission
line, and a switching center, having:
a) an analog feedback device for coarse setting of a line voltage level on the transmission line as a function of a line current
which is detected in the line driver; and
b) a digital feedback device, which is coupled to the analog feedback device via an analog/digital converter and a digital/analog
converter and has a single digital feedback path having a feedback filter device for fine setting of an amplitude and phase
relationship between the line voltage level and the line current, wherein
c) the feedback filter device is designed such that a filter input signal can be converted to a filter output signal at a
rate which is lower than the sampling rate of the analog/digital converter, wherein
d) the feedback filter device comprises a first recursive filter unit, a non-recursive filter unit connected in parallel with
the first recursive filter unit, and a second recursive filter unit which is connected in series with the parallel circuit
formed by the first recursive filter unit and the non-recursive filter unit; and wherein
e) the digital feedback device comprises a processing unit for carrying out signal processing in order to provide the switching
center with a processed output signal, wherein the filter input signal is also supplied to the processing unit.
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