DSP

1
DSP

• ???? ???? 8
• ADC Analog to Digital Converter

2
????? ?-ADC

• ???? ??? ?????? (???? ????)
• ???? ??????? (???? ????) ?????

???? Anti-Aliasing
DSP
ADC
DAC
??? ??????
??? ??????
??? ???????
3
???? ???? ?? ADC
???? Anti-Aliasing
Quantizer
S/H
Buffer/ Bus
??? ??????? (??????)
??? ??????? ?????
??? ?????? ??? ??? ??????? ?? ??? ???? ??????
4
Sample and Hold

• ???? - ???? ??? ?????? ???? ???????
• ??? ?????? HOLD ???? ???? ?????? ??
  ?-Quantizer

5
Quantizer - ?????

• ???? ????? ??? ???????? ????? ??? ?????????
  Quantization
• ????? ???? ??? ????????? ???? ??????
  SignMagnitude, Twos Complement, Ones
  Complement ????.
• ???? ???? ???? ?????????? ??? 2B ???? B ??? ????
  ?????? ??????.

6
Quantizer ????? (????)
7
?????? ADC

• Voltage to Voltage
• Voltage to Frequency
• Voltage to Time

8
??????? ?? ???? ADC (Voltage to Voltage)

• Flash
• Subranging
• Successive Approximation
• Sigma-Delta (??)

9
ADC - FLASH
10
ADC FLASH (????)

• ???? ??? ?? ?-Priority Encoder

• ???? ??? ?? ???? ???? S/H
• ????? ???? ??? ?-ADC (Conversion time 20nSec)
• ??? ????, ???? ????? ?? 10bit (?? bit ???? ????
  ???? ?? 2)

11
Subranging ADC

• ADC1 ?-ADC2 ???? Flash
• ??? ???? ?-Flash ????? ????
• ??? ???? ???? ???? ????? ???? ????? ?? ?-DAC
• ?????? ??????? ????? ????? ?? ?-DAC

12
Successive Approximation

• ???? n ?????? ???? ???? ???? ?? n ?????
• ???? ???? ?-Flash ??-Subranging
• ??? ???? ?-Flash ??-Subranging
• ?????? ??????? ????? ????? ?? ?-DAC
• ????? ???? ??????

13
Successive Approximation (????)
14
Sigma-Delta (??)

• Delta modulation
• ????? ?-ADC ????? ?? ????? (?) ??? ??? ??????
  ?????? ???? ?????? ?????, ????? ?-quantizer ?????
  ????? ?????? ???? ??????.
• ??? ????? ?? K ????? ?????.
• ?? ????? ???? ?? B ????? ??????? Quantizer ?? ???
  1 ????? K2B.
• ??? ????? ???? ????? ????????? ?????? ?"? ???? LP
  ?????.
• ???? ?????? ???????? ????? ?"? ?????? ?? ???
  ?????? ???? ????? (????? ???????).

15
Sigma-Delta (??) - ????

• Sigma - Delta modulation
• ????? ?-ADC ????? ?? ????? (?) ??? ??? ??????
  ?????? ???? ?????, ????? ?-quantizer ????? ?????
  ?????? ????? ???? ?????.
• ??? ????? ?? K ????? ?????.
• ??????? ????????? ?? ?-Delta modulation.
• ???? ?????? ???????? ????? ?"? ?????? ?? ???
  ?????? ???? ????? (????? ???????).

16
Sigma-Delta (??) - ????

• ?-ADC ????? ?????
• ??? ????/???? ???? ????? (???? ???? ?????)
• ??? ???? ???? ????
• ????? ???? ??????
• ?????? ??????? ????? ???????? ?? ????

17
?????? ???????(Speed v. Resolution)