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

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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

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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

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

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Demo Film1 Play CD Film1 http://www.youtube.com/watch?v=582E_OXeVOU Film2 Input signal voltage shift Film2 http://www.youtube.com/watch?v=uBhcLwn46QM&fea ture=youtu.be Film3 Sleep mode Film3 http://www.youtube.com/watch?v=Q74URMVuhF8&fe ature=youtu.be 5

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The Structure of DAC module 6

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Input: PCM 7

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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

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Eleven PWM Signals 9

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

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Matlab Simulation: Noise is pushed to higher frequencies 11

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Using Filter to Cutoff Noise 12

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

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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

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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

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

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Clock Synchronization and Data Extraction 17

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Clock Synchronization 44.1kHz frame rate2 channel 32 data2 phase 5.6448MHz Keep detecting : temp1=temp2=temp3 & temp4=temp5=temp6 Then generate sampling clock @ center pulse 18

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Clock Synchronization(cont.) 19

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Data Extraction 20

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Data Extraction(cont.) Keep detecting frame header 11100010 or 00011101 | 11100100 or 00011011 21

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Sleep Mode(Power Saving) system 22

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

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Reference http://en.wikipedia.org/wiki/Delta-sigma_modulation http://www.cscamm.umd.edu/programs/ocq05/adams/ad ams_ocq05.pdf http://www.cscamm.umd.edu/programs/ocq05/adams/ad ams_ocq05.pdf http://www.beis.de/Elektronik/DeltaSigma/DeltaSigma.ht ml http://www.beis.de/Elektronik/DeltaSigma/DeltaSigma.ht ml http://www.intersil.com/data/an/an9504.pdf http://hephaestusaudio.com/media/2009/07/MASH- Delta-Sigma.pdf http://hephaestusaudio.com/media/2009/07/MASH- Delta-Sigma.pdf 24

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Thank you! Q and A 25