To process an ultra-wideband signal with narrower-band ADCs, frequency-interleaved (FI) receiver technique that divides an ultra-broadband signal to narrower-band signals has been reported to date. Conventional FI-ADCs use analog filters such as LC filters to divide an ultra-wideband signal to separated narrower band signals. However, aliasing and level deviation of the signals that occurs in crossover frequency region of the filters degrades the signal transmission quality of the receivers that use FI-ADCs. To omit these degradations and improve the signal transmission quality we propose FI ADCs with an RF equivalent ideal filter (EIF).