Sigma-delta modulator

A Sigma-Delta (ΣΔ) modulator for converting an analog input signal having a frequency bandwidth around a variable center frequency f0 to a digital output signal at a sampling frequency fs. The ΣΔ modulator comprises a quantizer (420) for generating the digital output signal and a loop filter for sha...

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Bibliographic Details
Main Authors Aboushady, Hassan, Badran, Tamer, Sayed, Alhassan
Format Patent
LanguageEnglish
Published 07.01.2020
Subjects
BASIC ELECTRONIC CIRCUITRY
CODE CONVERSION IN GENERAL
CODING
DECODING
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
TRANSMISSION
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Summary:A Sigma-Delta (ΣΔ) modulator for converting an analog input signal having a frequency bandwidth around a variable center frequency f0 to a digital output signal at a sampling frequency fs. The ΣΔ modulator comprises a quantizer (420) for generating the digital output signal and a loop filter for shaping the quantization noise. The loop filter comprises at least one subfilter (430, 410) centered around a frequency f0 and constant noise shaping coefficients (451, 452, 453). The ΣΔ modulator further comprises a tunable delay element (455), a frequency adjuster (480) for adjusting the sampling frequency fs such that the normalized center frequency f0/fs is constant, and a delay adjuster (490) for adjusting the loop delay td implemented by the quantizer and the tunable delay element (455), such that the normalized loop delay td/Ts falls in a predetermined range [tmin, tmax], where Ts=1/fs.
Bibliography:Application Number: US201716312865