pirate
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Like Berti is saying noise shaping in nature requires oversampling.
To my knowledge noise shaping can only occur in the delta sigma structure where the quantization error is processed by the loop filter which in the case on the delta modulation is an high pass filter (integrator; delta modulation).
Therefore if the sampling frequency is much higher than than the signal frequency, noise is being greatly reduced or shaped in the band of interest (ie: signal band).
Ideally you can operate a delta sigma slightly above the Nyquist rate provided an ideal brick wall high pass loop filter which is pretty much impossible to built.
I would recommend the first chapter Richard Shreier book and the original paper on the delta modulation
[http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471465852.html]
[H. Inose, Y. Yasuda, and J. Murakami, "A telemetering system by code modulation-Δ-Σ modulation." <i>IRE Transactions on Space Electronics and Telemetry, vol. 8, pp. 204-209, 1962]
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