Lecture 5 Oversampling and Noise Shaping XILIANG LUO

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 White Noise:

Oversampling improve A/D accuracy

Oversampling improve A/D accuracy

Oversampling improve A/D accuracy

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

Noise Shaping in A/D

Noise Shaping in A/D

Noise Shaping in A/D

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 1 st order noise-shaping for oversampled D/A quantization

Noise Shaping in D/A

Noise Shaping in D/A

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