A receive path ΔΣ frequency to digital converter

In this paper a novel architecture for a second order ΔΣ frequency-to-digital converter (FDC), aimed at receive path applications, is presented. The new architecture uses fractional-N division techniques in order to reduce the fullscale input range and out of band quantization noise when used to detect small deviation FM signals, relative to the reference frequency. The output is a single bit bitstream whose average density is an accurate representation of the instantaneous frequency deviations of the modulated IF signal