Abstract: A method and structure for automatically calibrating various paths within multi-channel analog integrated circuits is disclose. The invention calls for digital signal processing circuitry to correct for absolute gain differences in the multiple channels. A first reference channel is precision trimmed at manufacture and used by the digital processing circuitry as a reference for channel gain calibration. When the circuit is powered for use, the other channels are calibrated based on the trimmed and calibrated reference. The need for providing the circuitry to precision trim all other channels but one is avoided by this invention.

Abstract: CODECs and various other types of communication devices require timing information to enable them to transmit and receive digital information at the proper time. In the case of multiple CODECs on a single integrated circuit, this has typically required devoting terminals to provide separate transmit and receive frame synchronization pulses for each CODEC. Alternatively, a microprocessor interface may be included so that internal registers can be loaded with transmit and receive timing information. However, that approach limits timing flexibility. In the present invention, a "frame synchronization separation pulse" (FSEP) provides the separation in time between transmit and receive synchronization pulses. In this manner, the number of integrated circuit terminals required for synchronization may be reduced.