Background calibration of interleave timing errors in time-interleaved analog to digital converters
A method for performing background calibration of interleave timing errors in N order Time-Interleaved Analog to Digital Converters (TIADCs), according to which N samples of the input signal are acquired in N different phases and the time-interleave error of each phase is calculated. Then the sign of each of the time-interleave error is extracted and the errors are adjusted by adjusting the timing of erroneous phases. This process is repeated until all the errors are lower than a predefined level.
1. A method for performing background calibration of interleave timing errors in N order Time-Interleaved Analog to Digital Converters (TIADCs), comprising:
a. acquiring N samples of an input signal in N different phases;
b. calculating the time-interleave error of each phase, wherein the time-interleave error of a phase is the difference between auto-correlations of the input signal evaluated at both sides of the phase;
c. extracting a sign of each said time-interleave error;
d. adjusting the errors of all N difference phases by adjusting the timing of erroneous phases according to said sign; and
e. repeating steps b) to d) above until all said errors are lower than a predefined level.
2. The method of claim 1 , wherein said erroneous phases timing adjustment comprises delaying phases with negative errors that are followed by phases with positive errors.
3. The method of claim 1 , wherein said erroneous phases timing adjustment comprises advancing phases with positive errors that are preceded by phases with negative errors.
4. The method of claim 1 , wherein an average time-interleave error, which exceeds a predefined correction limit, is measured and corrected by adjusting the timing of all of the phases.
5. A method for performing background calibration of interleave timing errors in N order Time-Interleaved Analog to Digital Converters (TIADCs), comprising:
a. acquiring N samples of the input signal in N different phases;
b. calculating the time-interleave error of each phase;
c. extracting a sign of each said time-interleave error;
d. adjusting the errors of all N difference phases by adjusting the timing of erroneous phases according to said sign; and
e. repeating steps b) to d) above until all said errors are lower than a predefined level;
wherein an average time-interleave error, which exceeds a predefined correction limit, is measured and corrected by adjusting the timing of all of the phases.