Reducing transmit signal components of a receive signal of a transceiver using a shared dac architecture

Abstract

Embodiments of a method and apparatus of reducing transmit signal components of a receive signal of a transceiver are disclosed. One embodiment of an apparatus includes a transceiver that simultaneously transmits a transmit signal and receives a receive signal. The transceiver includes a transmit DAC that generates the transmit signal based on a transmit digital signal stream. The transmit DAC includes a plurality of transmit DAC circuit elements, and a plurality of transmit DAC switches that control which of the plurality of transmit DAC circuit elements contribute to generating the transmit signal. The transceiver additionally includes an echo cancellation DAC that generates an echo cancellation signal based on the transmit digital signal stream. The echo cancellation DAC includes a plurality of echo cancellation DAC circuit elements, and a plurality of echo cancellation DAC switches that control which of the plurality of echo cancellation DAC circuit elements contribute to generating the echo cancellation signal. A data controller receives the transmit digital signal stream, and controls both the plurality of transmit DAC switches and the plurality of echo cancellation DAC switches. A canceller (summer) cancels at least a portion of the receive signal by summing the echo cancellation signal with the receive signal.