A CMOS subscriber line audio processing circuit including adaptive balance

The design of a CMOS subscriber-line audio processing circuit including self-adaptive trans-hybrid balance has been described. Its transmission performance has been shown to exceed CCITT specifications with up to 12 dB of transmit gain and receive loss. This has been achieved using a single 5-V power supply while maintaining simple analog interfaces to a subscriber line interface circuit. This circuit will enable the design of programmable and flexible line cards, superior transmission performance over those realized with more conventional components.<
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