Edwards Angell Palmer & Dodge LLP
ΣΔ-analog-to-digital modulator and digital filter for improved noise immunity
A ΣΔ analog-to-digital converter has a ΣΔ modulation section which executes ΣΔ modulation, and a digital filter which filters a digital signal output from the ΣΔ modulation section. The digital filter has gain properties that one of dips of a gain of the digital filter corresponds to a noise frequency which is, for example, the commercial frequency 60 Hz. Especially, the lowest frequency of the dips corresponds to the noise frequency.
Yokogawa Electric Corporation
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additional additional inventional
Naoki Makoto
Maeda Takeuchi