Understanding Delta-Sigma Data Converters
Citations
18 citations
Cites background or methods from "Understanding Delta-Sigma Data Conv..."
...DSM, the modulator accurately estimates the input signal by averaging a number of samples even though the instantaneous output is very coarse [21]....
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...can be used to evaluate how the DSM affects the signal response from its input to the output [21]....
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18 citations
18 citations
Cites background or methods from "Understanding Delta-Sigma Data Conv..."
...The out-of-band gain needs to be reduced to stabilize the high-order modulator at the expense of increasing quantization noise as well as the circuit complexity owing to additional coefficient paths [2]....
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...Moreover, due to the feedforward and oversampling properties, the signal transfer function (STF) of the first loop approximates unity....
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...However, the perfect matching between analog and digital transfer functions in MASH modulators is highly required to eliminate the quantization noise of the preceding stages, otherwise the noise leakage will deteriorate the overall performance significantly [2]....
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...enormous as in audio-bandwidth applications (a large OSR employed) [2]....
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...Then, C(z) can be approximately expressed as, C(z) ≈ 1 − (ε1 + ε2 + εa) (34) Combining (31) and (34), NTF1(z) will become, NT F1(z) ≈ (1 − z −1)2 1 − (ε1 + ε2 + εa) ≈ [1 + (ε1 + ε2 + εa)](1 − z−1)2 (35) Also, combining (27) and (35), STF1(z) can be calculated as, ST F1(z) = Ls1(z) 1 − Ln1(z) = B(z) (1 − z−1)2 · [1 + (ε1 + ε2 + εa)](1−z −1)2 = [1 + (ε1 + ε2 + εa)] · B(z) (36) Ignoring the last two terms with high pass filtering of B(z) in (30) within band of interest, then STF1(z) becomes, ST F1(z) = [1 − (ε1 + ε2 + εa)2]z−1 ≈ z−1 (37) As a result, Y1(z) can be finally approximated by, Y1(z) ≈ z−1 X (z) + (1 + ε1st)(1 − z−1)2 E1(z) ε1st = ε1 + ε2 + εa (38)...
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17 citations
Cites background from "Understanding Delta-Sigma Data Conv..."
...9) is much less susceptible to limit cycles, which would create distortion in the modulator output and limit dynamic range [29]....
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...For a first-order CT modulator [28], [29], the STF and NTF are STF = 1 − z −1 s and NTF = 1 − z−1 where z = es ....
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17 citations
References
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