Bandpass delta-sigma analog-to-digital converters

An apparatus includes a delta-sigma analog-to-digital converter for digitalizing an analog input signal. The Δ-Σ ADC includes an analog band-pass loop filter 20 configured to filter an analog signal derived from the analog input signal and a quantizer 22 configured to produce a series of digital signals by sampling the filtered analog signal from the loop filter at a sampling frequency f. The loop filter has a center band-pass frequency f. The series of digital signals has a data-carrying frequency spectrum that is a mirror image of a data-carrying frequency spectrum of the analog input signal. The data-carrying frequency spectrum of the series is located between the center band pass frequency and zero.