| 摘要 |
Methods for calibrating a plurality of N time-interleaved analog-to-digital converters (ADCs) for any integer N>=2 by detecting and/or correcting timing and amplitude errors therein, where each of the ADCs, numbered j=1, 2, . . . , N has an identical clock frequency fc and period Tc=(fc)-1. Ideally, the N ADCs are clocked uniformly in time so that two consecutively clocked ADCs number j1 and j1+1 have effective sampling times that differ by time intervals of uniform length (Delta)t=Tc/N. Ideally, the N ADCs also have identical gains from their analog input signals to their digital output signals. In a calibration procedure, all ADCs receive a common analog input signal Sin(t)=Asin(2 (pi)(1+s)fct), where s is a non-zero fractional number satisfying -0.5<s<0.5. The output signal values from ADC number j provide a set of ordered pairs of values (ti, Dij) for sampling times ti, and the set of values (Dij)i with j fixed is approximated by another set of values ( Vij=Ajsin(2 (pi)sfcti+(phi)j))i. Here, the amplitudes Aj and phase angles (phi)j are chosen to provide a best numerical fit to the set (Dij)i for each j=1, 2, . . . , N, according to some criterion. The phase differences (Delta)(phi)j2,j1=(phi)j2-(phi)j1 are then determined and compared with the ideal phase difference value (Delta)(Phi)j2,j1=2 (pi)(j2-j1)/N to determine if a relative timing error exists between ADCs number j1 and j2. In a similar manner, the amplitude differences Aj2-Aj1 are compared to determine if a relative gain error exists between ADCs number j1 and j2.
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