Richard Schreier的Delta-Sigma 在MIT的讲义MITOPENCOURSEWARE
MASSACUSETTS INSTITUTE OF TECHNOLOGY 6.976 High-Speed Communication Circuits and Systems Lecture 29 Lowpass and Bandpass Delta-Sigma Modulation Richard Schreier
ANALOG DEVICES
Copyright 2003 Richard Schreier
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Outline
1 Σ Basics
1st-Order Modulator
2 Advanced Σ
High-Order Σ Modulators Multi-bit and Multi-Stage Modulation
3 Bandpass Σ Modulation 4 Example Bandpass ADC
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1. Σ Basics
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CTMOD1: A 1 -Order Continuous-Time Σ Modulator
The input signal, U, is converted into a sequence of bits, V ∈ (0,1).
C R U Y CK 0,I V
st
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Properties of CTMOD1
DC Inputs
Integrator ensures that input current is exactly balanced by the (average) feedback current
“Innite resolution”
Signals which alias to DC are rejected
“Inherent anti-aliasing”
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Non-ideal Effects in CTMO……
