1. The Design of a Delta Sigma Modulator Presented by: Sameh Assem Ibrahim 24-July-2003

2. Introduction Oversampling: f s > 2f m, OSR = f s /2f m > 1 Advantage 1: Relax anti- aliasing filter Advantage 2: Reduce in-band quantization noise and thus increase SNR Note that: A quantized signal ampled at (fs) will have all its noise power folded into the frequency band extending from 0 to (fs/2)

3. The need for delta sigma modulation Nyquist converters: SNR = 1.76 + 6.02n Overampled: SNR = 1.76+6.02n+10log(OSR) Solution is Noise shaping through delta sigma modulators

4. Proposed Architecture and Specifications ΣΔ Modulator Analog input Decimator Digital F S Analog Output F N 1 bitMultiple bits Integrator 1-Bit D/A ++ -- x(n) y(n) fsfs 3.3V Supply Voltage <130 mW Power consumption 20 kHz Input signal BW 128 OSR 60dB SNR 2V Reference Voltage

5. Simulink Model Integrator1Integrator2 Comparator (1 bit Quantizer) DAC To achieve stability

6. Circuit Used

7. Simulation Results