BÁO CÁO PAM.docx

8/11/2019 BO CO PAM.docx

1/13

1

I HC S PHM K THUT TPHCM

BO COPAM/PWM/PPM MODULATIONDEMODULATION

TRAINERMODEL-COM208

[Type the document subtitle]

NHM 3:NGUYN CHNH TM

TRNG TN LCNGUYN S


2/13

I - C S L THUYT1. IU CH BIN XUNG (PAM)

- PAM l qu trnh chuyn i tin tc t dng sng tng t sang dng tnhiu sthng qua qu trnh ly mu.- L tn hiu a mc,mi mc bin ng vi k hiu M -ary(tng ngn=bit)

Vi cng tc d liu,phng php ny yu cu bng thng nh .


3/13

2.

IU CH RNG XUNG (PWM)nh ngh tt nht ca iu ch rng xung (Pulse Width Modulation -PWM) c l l chnh tn gi ca n. C ngha l thay i rng caxung.

phng php so snh toc bng phng php so snh ta cn:

+ Tn hiu rng ca : Xc nh tn s ca PWM+ Tn hiu ta (Ref) l tn hiu xc nh mc cng sut iu ch (Tnhiu DC).


4/13

- iu quan trng nht cn ch ca mt tn hiu PWM chnh l chu k v tn s ca n.N lun khng i. Ch c thi gian ON (xung mc cao) vthi gian OFF (xung xung mc thp) l thay i. D hiu hn l c thi gianON tng th thi gian OFF s phi gim v ngc li tng thi gian ON vthi gian OFF l khng i, l chu k ca PWM.

3. IU CH PHA XUNG (PPM)- iu ch v tr xung PPM (Pulse position Width Modulation): c rng xung ging nhau nhng v tr xung thay i theo bin .

4. IC 4013

- Chc nng: thanh ghi dch, b m, mch iu khin- S chn


5/13

- IC 4013 c cu to t 2 flip flop loai Dc lp nhau.Khi ngvo mc thp th ng ra mc thp v ngc li.

5. IC 4053- Chc nng: a hp v gii a hp tn hiu tng t-

S chn

6. IC 4046- Chc nng: - vng kha pha

B to dao dng

-

S chn


6/13

- ng dng:

iu ch v gii iu ch FM Tng hp v nhn tn s So snh tn s ng b d liu Chuyn i in p sang tn s

IIM PHNG1. PAM

iu ch


7/13

2.

PWM

iu ch

3.

PPM

iu ch

IIIKHO ST1. PAM

Tn hiu cn iu chf=1khz v Vpp= 1V


8/13

Tn hiu ly muf=8.569 khz v Vpp= 5.52V

Tn hiu c iu ch khi cng tc v tr NTc f=1khz v Vpp=0.88 V

Tn hiu c iu ch khi cng tc v tr S\H


9/13

Hot ng:- khi a 2 tn hiu iu ch v tn hiu ly mu vo b nhn th tn hiu c

nhn li cng vi c ch np x ca t 0.1/ 100 PPC rt nh nn tn hiu ciu ch.

Tn hiu gii iu chc f=1khz v Vpp= 0.648 V

Hot ng:- Tn hiu PAM a qua b lc thng thp loi b cc tn s cao.Kt lun:

_ Tn hiu ng ra iu ch v gii iu ch c bin b suy gim.

2.

PWMTn hiu iu chf=1khz v Vpp= 1V


10/13

Tn hiu xung tam gic f= 10Khz v Vpp= 4V

Tn hiu c iu chf= 10Khz v Vpp= 5.28V


11/13

Hot ng: khi a 2 tn hiu iu ch v xung tam gic qua b so snh th tnhiu iu ch c so snh vi tn hiu xung tam gic da trn chu k ca xungtam gic.

Tn hiu gii iu chf= 10Khz v Vpp= 1.28V

Hot ng:- Tn hiu PWM v tn hiu DC 1V c a vo b so snh, ngra l tn hiu c gii iu ch.- lm nhn tn hiu ta a tn hiu trn qua b lc thng thp ctn s ti 3.4Khz loi b cc tn s cao.Nhn xt:tn hiu ng ra c bin c khuyech i.

3. PPMTn hiuciu ch f= 1Khz v V

pp= 5.2V


12/13

Hot ng:- a 2 tn hiu iu ch v tn hiu xung tam gic vo b so snh, ngrany a n b ly mu to ra 2 tn hiu khc l a1 v a2 sau a qua

b nhn.Ng ra ny l tn hiu PPM.

Tn hiu gii iu chf= 0.5Khz v Vpp= 8.4V

Hot ng:- Tn hiu PPM c so snh vi tn hiu DC 1V thng qua b so snhng ra ny l tn hiu xung tam gic .- Tn hiu ny c a dn b chia v b lc thng thp tn s ti 3.4Khz loi b cc tn s cao.


13/13

KT LUN- Ty vo nhu cu m ta s dng cc kiu iu ch khc nhauV d: pam th tn s khng i nhng bin b suy gim, pwm c tn skhng i nhng bin c khuyech i.

IV - NG DNG- Ta thng ng dng iu ch truyn thng tin i xa .Cc tn hiutng t c bin i thnh cc tn hiu s.Nh vy y l bc u bini tn hiu t tng t sang s.- iu chc ng dng nhiu trong iu khin. Ly in hnh nht mchng ta thng hay gp l iu khin ng c v cc b bm xung p, iup... S dng PWM iu khin nhanh chm ca ng c hay cao hn na ncn c dng iu khin n nh tc ng c.

- Ngoi lnh vc iu khin hay n nh ti th PWM n cn tham gia v

iu ch cc mch ngun nh l: boot, buck, nghch lu 1 pha v 3 pha... PWMchng ta cn gp nhiu trong thc t v cc mch in iu khin. iu c

bit l PWM chuyn dng iu khin cc phn t in t cng sut c

ng c tnh l tuyn tnhkhi c sn 1 ngun 1 chiu c nh.

Nh vy, PWM n c ng dng rt nhiu trong cc thit b in in t.

iu m dn in in t d dng nhn ra l PWM chnh nhn t m cc i

Robocon s dng iu khin ng c hay n nh tc ng c.

BÁO CÁO PAM.docx

Documents

Transcript of BÁO CÁO PAM.docx