A time-interleaved ADC multiplexed by a blue-noise randomization method

In this paper, we propose a method to implement the randomization selection sequence in a time-interleaved (TI) ADC system. The proposed randomization sequence generator is one with blue noise spectral characteristics (high-frequency noise). This selection method guarantees that each individual channel would be selected with the lowest possible rate in order to maintain low speed requirements while still maintaining the random nature so as to effectively spread the harmonic distortions created by channel offset and gain mismatch. The blue-noise channel selection is achieved through the use of an all-digital ZA modulator. Additionally, a randomized TI ADC system employing blue-noise choppers at the input and output is proposed. This structure reduces the effects of 1/f noise and average channel offset on the TI ADC system. The proposed blue-noise randomized TI ADC with blue-noise choppers demonstrates through simulations an improvement in SFDR of up to 17 dB over traditional periodic TI ADCs and 13 dB with respect to other randomized TI ADCs