Calibration of impairments in a multichannel time-interleaved adc

A method comprising:

• generating a plurality, M, of clock signals, with at least some of clock signals having a different one of a selected plurality of clock phases, where a is phase difference between selected clock phases depends on a value of M;
• converting an input signal with a plurality, M, of Analog to Digital Converters (ADCs) coupled to the M clock signals, to provide to a set of ADC outputs as M digital signals, each of the ADCs having at least one of an offset correction input, a gain correction input, or a phase correction input;
• interleaving the M digital values output by the ADCs to form a digital representation of the input signal;
• converting the input signal with a reference ADC to output reference digital values in response to at least one of the M clock signals;
• and
• estimating one or more correction signals for at least one of offset, gain, and phase error in at least one of the ADCs by:
• determining a set of selected digital values from one of the M digital signals over a predetermined number of ADC output samples;
• determining a set of reference values over a predetermined number of ADC output samples;
• comparing the set of selected digital values and the set of reference values, to produce a comparison result;
• accumulating the comparison result to provide an error estimate;
• and
• from the error estimate, determining at least one of an offset, gain or phase correction corresponding to one or more correction signals to be applied to correct at least one of offset, gain, or phase error of at least one of the ADCs.

A system comprising:

• a radio frequency amplifier, for receiving an input radio frequency signal;
• a translator, for down converting the input radio frequency signal to a received signal;
• an M-channel time-interleaved analog to digital converter (MCTIADC) connected to the received signal and to provide a digitized received signal, the MCTIADC further comprising:
• a plurality, M, of Analog to Digital Converters (ADCs) for converting the received signal to a set of ADC outputs as M digital values, each of the ADCs having at least one of an offset correction input, a gain correction input, or a phase correction input;
• a multiplexer, for interleaving the M digital values output by the ADCs to provide the digitized received signal;
• at least one reference ADC coupled to the received signal, and to output a reference digital value;
• and
• an adaptive processor, for estimating at least one of an offset, gain or phase error in at least one of the ADCs from the set of ADC outputs and the reference digital value, and generating one or more correction signals to be applied to one of the offset, gain, or phase correction inputs of at least one of the ADCs;
• and
• a digital demodulator, connected to the digitized received signal, and to provide a digital demodulated signal.