Patent ID: 11923866
Assignee: REALTEK SEMICONDUCTOR CORPORATION
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 6:
7. A digital-to-analog conversion method having signal calibration mechanism, comprising:
controlling an operation state of each of a plurality of current sources to be one of a first current output state and a second current output state, by a digital-to-analog conversion (DAC) circuit comprising the current sources each having a current offset, according to an input digital codeword comprised by an input digital signal, so as to generate an output analog signal according to a total current of the current sources, wherein each of the current sources outputs a current with a same current amount but opposite signs respectively under the first current output state and the second current output state;
processing the output analog signal to generate an echo signal by an echo transmission circuit;
receiving the input digital signal and performing mapping from a codeword offset mapping table according to the input digital codeword by a calibration circuit to generate an offset, wherein the codeword offset mapping table comprises a one-to-one correspondence relation between a plurality of codewords and a plurality of codeword offsets;
processing the offset according to a group of echo-canceling coefficients by an echo-canceling circuit to generate an echo-canceling signal;
generating an offset amount according to a difference between the echo signal and the echo-canceling signal by a calibration parameter calculating circuit;
categorizing the offset amount corresponding to the different input digital codeword into a plurality of groups according to the operation state of each of the current sources to perform statistic operation by the calibration parameter calculating circuit;
setting each of the current sources as a target current source to perform calculation among the groups by the calibration parameter calculating circuit such that the current offset of each of the current sources besides the target current source cancels out to calculate the current offset of the target current source; and
converting the current offset of the current sources to the codeword offsets to update the codeword offsets in the codeword offset mapping table by the calibration parameter calculating circuit.