On the design of tone-free ΣΔ modulators

Traditional one-bit ΣΔ modulators used for A/D and D/A conversion produce very predominant tones near half the sample rate which might intermodulate in the analog converter section and cause in-band tones. This paper demonstrates how the use of chaos can substitute dither as a means for extinguishing these tones. Especially, modulator feedback filters derived from noise transfer functions having an all-pass term seem very promising