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Lecture 5 : Oversampling and Noise Shaping. Xiliang Luo 2014/10. Oversampling improve A/D accuracy. Oversampling improve A/D accuracy. WSS. Oversampling improve A/D accuracy. Oversampling improve A/D accuracy. Oversampling improve A/D accuracy. Oversampling improve A/D accuracy.
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Lecture 5: Oversampling and Noise Shaping Xiliang Luo 2014/10
Oversamplingimprove A/D accuracy White Noise:
Noise Shaping in A/D To make a significant reduction of number of quantization bits, the required oversampling ratio is too much, which is too costly Oversampling + noise spectrum shaping much higher gain
Noise Shaping in A/D Direct quantization uniform noise PSD Noise shaping non-uniform noise PSD, preferably, most noise is outside the signal band!
Noise Shaping in A/D Noise-shaping quantizer, aka sampled-data Delta-Sigma modulator 1-bit
Noise Shaping in A/D PSD after downsampling
Noise Shaping in A/D Direct Quantization: Noise Shaping:
Noise Shaping in D/A quantization error
Noise Shaping in D/A 1st order noise-shaping for oversampled D/A quantization
Summary • 1. Nyquist-Sampling • 2. Process continuous time signal with discrete system • 3. Downsampling/Upsampling • 4. Polyphase decomposition • 5. D/A, A/D, Noise Shaping