It is shown that for delta-sigma (ΔΣ) frequency-to-digital conversion (FDC) there is no need for a ΔΣ modulator, since a limited FM signal itself may be considered as an asynchronous ΔΣ bit-stream. By feeding the limited FM signal directly to a sinc2 ΔΣ decimator, a triangularly weighted zero-crossing counter FDC is introduced, providing ΔΣ noise shaping . The results measured confirm the theory.
- Frequency converters
- Sigma-delta modulation
ASJC Scopus subject areas
- Electrical and Electronic Engineering