Codec circuit for POTS system
AssigneeLantiq Deutschland GmbH
InventorsChristian Jenkner, Gerhard Noessing, Richard Gaggl, Joachim Pichler
Life of this patent
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Abstract
A CODEC circuit for POTS system comprises a digital circuit for outputting a digital control signal having a first bit width, the digital control signal being indicative of a voltage to be applied to a POTS subscriber line pair. Further, the CODEC comprises a noise shaper coupled to an output of the digital circuit for generating a noise-shaped control signal and a digital-to-analog converter coupled to an output of the noise shaper, the input of the digital-to-analog converter having a second bit width being larger than 1 and smaller than the first bit width.
Claims39
An apparatus that drives a subscriber line pair to a target DC line current, the apparatus comprising:
- a current detector that senses an actual DC line current on the subscriber line pair;
- a feedback loop that feeds back a control variable of the current based on the sensed actual DC line current;
- a noise shaper that shapes a control signal based on the control variable such that a quantizer error of the control signal is minimized;
- a generator that generates a DC line current to drive the subscriber line pair;
- and
- a controller that adjusts the control variable such that the actual DC line current is adjusted to be equal to the target DC line current.
A method for driving a subscriber line pair to a target DC line current, the method comprising the steps of:
- sensing an actual DC line current on the subscriber line pair;
- feeding back a control variable of the current based on the sensed actual DC line current;
- noise shaping a control signal based on the control variable such that a quantizer error of the control signal is minimized;
- generating a DC line current to drive the subscriber line pair;
- and
- controlling the control variable such that the actual DC line current is adjusted to be equal to the target DC line current.
Dependencies are inferred from the claim text.