Selectable intermediate frequency sigma-delta analog-to-digital converter

摘要: A sigma-delta analog-to-digital converter (10) provides high loop gain for suppression of noise components by use a regenerative feedback or resonator (50), which produces comb resonance response 212), embedded in the main degenerative (48). The includes an ADC (32) samples at clock frequency, turn defines Nyquist frequency. also DAC (38) has transfer function (42), is equalized filter (44). (50) low-pass (52) matches function, DC block (56), and null (54) nulls peak lies above open-loop set to unity 0°±N 360° phase frequency analog input signal. multipole embodiment (510) multiple loops (55o) produce rejection (642). Resonators (751) are used other ΣΔ ADCs (790, 890).