Codec circuit for POTS system

摘要

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.

主权项

1. 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.