Apparatus and method for calibrating mismatches of time-interleaved analog-to-digital converter
An apparatus and a method of correcting a mismatch of a time-interleaved analog-to-digital converter are provided. The apparatus may include: a time-interleaved analog-to-digital converter configured to receive a non-return-to-zero (NRZ) signal in a correction mode and generate a first output signal, and including a plurality of analog-to-digital converters; and a mismatch corrector configured to generate a second output signal by processing the first output signal of the time-interleaved analog-to-digital converter based on parameters, wherein the parameters may be generated based on the first output signal of the time-interleaved analog-to-digital converter in the correction mode, and a period of the NRZ signal may be different from a product of a sampling period of the time-interleaved analog-to-digital converter and a number of the plurality of analog-to-digital converters included in the time-interleaved analog-to-digital converter.
1. An apparatus comprising:
a time-interleaved analog-to-digital converter configured to receive a non-return-to-zero (NRZ) signal in a correction mode and generate a first output signal, and comprising a plurality of analog-to-digital converters; and
a mismatch corrector configured to generate a second output signal by processing the first output signal from the time-interleaved analog-to-digital converter based on parameters,
wherein the parameters are generated based on the first output signal of the time-interleaved analog-to-digital converter in the correction mode, and
wherein the NRZ signal is a pulse signal having a period different from a product of a sampling period of the time-interleaved analog-to-digital converter and a number of the plurality of analog-to-digital converters comprised in the time-interleaved analog-to-digital converter.
2. The apparatus of claim 1 , further comprising:
a pattern generator configured to generate the NRZ signal in the correction mode;
a mismatch detector configured to detect mismatches of the time-interleaved analog-to-digital converter based on the second output signal in the correction mode; and
a parameter generator configured to generate the parameters based on the mismatches in the correction mode.
3. The apparatus of claim 2 , wherein the mismatch detector comprises:
a filter configured to remove a frequency component of the NRZ signal from the first output signal and output a spur signal; and
a power estimator configured to compute power of spurs based on the spur signal from the filter.
4. The apparatus of claim 3 , wherein the filter comprises a notch filter configured to remove harmonics of the NRZ signal.
5. The apparatus of claim 2 , wherein the parameter generator is further configured to generate the parameters based on a genetic algorithm.
6. The apparatus of claim 5 , wherein the mismatches comprise a magnitude of spurs except for frequency component of the NRZ signal from the first output signal, and
wherein the parameter generator is further configured to evaluate a fitness of the parameters based on the magnitude of the spurs.
7. The apparatus of claim 6 , wherein, based on the magnitude of the spurs being equal to or less than a predetermined threshold, the parameter generator is further configured to terminate the genetic algorithm.
8. The apparatus of claim 1 , wherein a duty cycle of the NRZ signal is less than or equal to an inverse of the number of analog-to-digital converters comprised in the time-interleaved analog-to-digital converter.
9. The apparatus of claim 1 , wherein a greatest common divisor of a value obtained by dividing the period of the NRZ signal by a sampling period and the number of analog-to-digital converters comprised in the time-interleaved analog-to-digital converter is 1.
10. The apparatus of claim 1 , wherein, when P and K are integers greater than 0, the mismatch corrector is further configured to process the first output signal based on K stages, each of the K stages computing a P-order equation, and
wherein the parameters comprise at least one coefficient of the P-order equation.
11. The apparatus of claim 10 , wherein the parameters comprise a gain, and
wherein the mismatch corrector is further configured to multiply the first output signal by the gain.
12. The apparatus of claim 1 , further comprising:
an offset detector configured to detect offsets of the time-interleaved analog-to-digital converter based on the first output signal in the correction mode,
wherein the mismatch corrector is configured to add the detected offset to the first output signal.
13. A method of correcting mismatch of a time-interleaved analog-to-digital converter comprising a plurality of analog-to-digital converters, the method comprising:
providing a non-return-to-zero (NRZ) signal to the time-interleaved analog-to-digital converter in a correction mode;
generating parameters based on a first output signal of the time-interleaved analog-to-digital converter in the correction mode; and
generating a second output signal by processing the first output signal based on the parameters,
wherein the NRZ signal is a pulse signal having a period different from a product of a sampling period of the time-interleaved analog-to-digital converter and a number of the plurality of analog-to-digital converters comprised in the time-interleaved analog-to-digital converter.
14. The method of claim 13 , wherein the generating the parameters comprises measuring a magnitude of spurs except for a frequency component of the NRZ signal in the first output signal.
15. The method of claim 14 , wherein the generating the parameters further comprises evaluating a fitness of the parameters based on the magnitude of the spurs, according to a genetic algorithm.
16. The method of claim 13 , wherein, when P and K are integers greater than 0, the generating the second output signal comprises processing the first output signal based on K stages, each of the K stages computing a P-order equation, and
wherein the parameters comprise at least one coefficient of the P-order equation.
17. The method of claim 13 , further comprising detecting an offset of the time-interleaved analog-to-digital converter based on the first output signal,
wherein the parameters comprise a gain, and
wherein the generating the second output signal comprises:
adding the offset to the first output signal; and
multiplying the gain by the first output signal to which the offset has been added.
18. A method of correcting mismatch of a time-interleaved analog-to-digital converter comprising a plurality of analog-to-digital converters, the method comprising:
providing a pulse signal to the time-interleaved analog-to-digital converter in a correction mode to control the time-interleaved analog-to-digital converter to generate a first output signal;
generating parameters based on the first output signal output from the time-interleaved analog-to-digital converter; and
generating a second output signal by processing the first output signal based on the parameters,
wherein the generating the parameters comprises evaluating a fitness of the parameters, according to a genetic algorithm,
wherein the pulse signal is a non-return-to-zero (NRZ) signal,
wherein the generating the parameters further comprises measuring a magnitude of spurs except for a frequency component of the NRZ signal in the first output signal, and
wherein the fitness is dependent on the magnitude of the spurs.
19. The method of claim 18 , wherein, when P and K are integers greater than 0, the generating the second output signal comprises processing the first output signal based on K stages, each of the K stages computing a P-order equation, and
wherein the parameters comprise at least one coefficient of the P-order equation.