Group member: Zhaoxin Mamengduo Cfang Stanley The Implementation of Delta-Sigma Modulation in Digital-to-Analog Converter 1

Project Idea Motivation: EE 505 CMOS Data Conversion circuits During the process of digital-to-analog converting Use Delta-sigma modulator to push noise in music to high frequency band Use speaker/headphone as the low-pass filter to filtrate high frequency white noise 2

Top Level Components Delta-sigma modulation Delta-sigma modulation Low pass filter PCM(digital) In Serial Pulse Width Modulation (PWM,digital) Signal In Serial 3

Level-shifter for DVD Output Signal Output signal(from DVD) voltage: -0.5V~+0.5V Schmidt trigger: SN74LS14N 4 rheostat

Demo Film1 Play CD Film1 Film2 Input signal voltage shift Film2 ture=youtu.be Film3 Sleep mode Film3 ature=youtu.be 5

The Structure of DAC module 6

Input: PCM 7

The 3-stage Delta-sigma Modulation Y 1 ＝ X+(1 － Z -1 )Q Y 2 ＝－ Q 1 ＋（ 1 － Z － 1 )Q 2 Y 3 ＝（－ Q 2 ）＋ (1 － Z -1 )Q 3 Y ＝ X+ （ 1 － Z － 1 ) 3Q 3 PCM PWM 8

Eleven PWM Signals 9

Output: PWM PWM: digital signal but has analog info. 10

Matlab Simulation: Noise is pushed to higher frequencies 11

Using Filter to Cutoff Noise 12

One Order Noise Shaping Model Q ＝ Y － U U － Y ＝－ Q U ＝ X － Q 13

One Order Noise Shaping Model U (n) ＝ X (n) － Q (n-1) Q (n) ＝ Y (n) － U (n) Y (n) ＝ X (n) － Q (n － 1) ＋ Q (n) ＝ X (n) ＋ Q (n) － Q (n － 1) Q (n) － Q (n － 1) ＝（ 1 － Z － 1 ）Q Y ＝ X ＋（ 1 － Z － 1 ）Q 14

The 3-stage Delta-Sigma Modulation Y 1 ＝ X+(1 － Z -1 )Q Y 2 ＝－ Q 1 ＋（ 1 － Z － 1 )Q 2 Y 3 ＝（－ Q 2 ）＋ (1 － Z -1 )Q 3 Y ＝ X+ （ 1 － Z － 1 ) 3Q 3 15

Clock Synchronization with DVD Input signal(from DVD) is in serial: Need to decode SPDIF signal So need to synchronize clock with DVD 16

Clock Synchronization and Data Extraction 17

Clock Synchronization 44.1kHz frame rate×2 channel ×32 data×2 phase ＝ MHz Keep detecting : temp1=temp2=temp3 & temp4=temp5=temp6 Then generate sampling center pulse 18

Clock Synchronization(cont.) 19

Data Extraction 20

Data Extraction(cont.) Keep detecting frame header or | or

Sleep Mode(Power Saving) system 22

Volume Control Matlab verification Lower volume: right shift Larger volume: left shift Debounce module( real world) 23

Reference ams_ocq05.pdf ams_ocq05.pdf ml ml Delta-Sigma.pdf Delta-Sigma.pdf 24

Thank you! Q and A 25