Thi Nghiem Do Luong Hvktqs

Bi Vn Sng - Mai Quc Khnh

Hng dn th nghim - thc hnh o lng in - v tuyn in

Hc vin k thut qun s h ni - 1999

Bi Vn Sng - Mai Quc Khnh


Hc vin k thut qun s H ni - 1999

t sch hc vin k thut qun s


nh my in t. In ti Xng in Hc vin K thut Qun s S lng 500 cun. Kh 19 x 27. In xong thng 12 nm 1999

Li gii thiu

o lng in - v tuyn in l mt lnh vc quan trng trong k thut thng tin o lng hin i, n c ng dng rt rng ri trong cc hot ng khoa hc cng ngh v thm nhp vo nhiu lnh vc ca nn kinh t quc dn. o lng in - v tuyn in trc ht l mt hot ng khoa hc k thut thc nghim, nh n ta c th nh gi, kim nghim c cc cng trnh khoa hc; c th xy dng c h thng s liu ca cc dy truyn cng ngh sn xut quc phng v dn dng, gp phn nng cao cht lng sn phm v hiu qu ca hot ng khoa hc thc nghim.

Vi nhng l do nu trn "o lng in - v tuyn in","Th nghim - thc hnh o lng in - v tuyn in" l hai mn hc quan trng khng th thiu c i vi ngnh o to "in-in t" Hc vin K thut qun s. Hai mn hc ny l mt th thng nht, khng th tch ri nhau vi cng mt mc ch chung l trang b cho hc vin kin thc v nng lc hot ng thc tin trong lnh vc o lng in - v tuyn in.

Theo tin trnh o to, hc phn "Th nghim - thc hnh o lng in - v tuyn in" c tin hnh sau khi kt thc mn hc "o lng in - v tuyn in". Trn nn kin thc o lng in - v tuyn in c trang b, hc vin c th nhanh chng tip cn vi phng tin o, thc hin c hiu qu cc ni dung th nghim, thc hnh.

Cn c vo chng trnh "Th nghim - thc hnh o lng in - v tuyn in" c Gim c Hc vin KTQS k ban hnh nm 1999, nhm tc gi gm ph gio s ph tin s Bi Vn Sng v thc s ging vin Mai Quc Khnh phi hp son tho ti liu ny.

Ti liu "Hng dn th nghim - thc hnh o lng in - v tuyn in" c chia thnh 8 bi v phn ph lc. Trong qu trnh son tho cc tc gi phi hp cht ch v thng xuyn tranh th s ng gp ca tp th cn b ging dy B mn L thuyt mch-o lng, ti liu nht qun v ni dung chuyn mn, hp l trong cch th hin. Tuy nhin ti liu vit ln u, da theo chng trnh mi c ph duyt, trn c s cc phng tin o hin c phng th nghim ca b mn, nn n khng trnh khi nhng sai st, rt mong s ng gp qu bu ca c gi.

i vi hc vin trc khi thc hin cc bi th nghim-thc hnh, phi nghin cu k ti liu ny v cc ni dung c lin quan a ra trong gio trnh "o lng in-v tuyn in". Trong qu trnh tin hnh th nghim- thc hnh, phn ln thi gian tp trung nghin cu v s dng cc nm iu khin v iu chnh ca phng tin o, tin hnh cc thao tc o lng- kim tra. Kt qu thu

nhn c mi bi th nghim-thc hnh tuyt i khng c vit vo mu cc bng kt qu trong ''Hung dn th nghim-thc hnh o lng in-v tuyn in''. Chnh v vy hc vin nn sao chp trc mu bo co th nghim-thc hnh (Ph lc 3), dng n in kt qu v vit bo co sau khi hon thnh hc phn th nghim-thc hnh.

Cc tc gi chn thnh cm n tp th cn b ging dy B mn L thuyt mch-o lng Hc vin KTQS , ph gio s ph tin s V Nh Giao c nhng gp b ch trong qu trnh bin son, hiu nh ti liu ny.

cc tc gi

Bi 1

ng dng cc phn mm MATLAB

v MATHCAD trong k thut m phng PT

v x l kt qu quan st

Mc ch - yu cu:

Sau khi hon thnh ni dung bi 1 hc vin phi :

Hiu c:

-S chc nng ca cc phng tin o v cc phng php o c bn s

dng trong hc phn th nghim-thc hnh;

-Cc bc x l kt qu quan st ca php o trc tip v gin tip.

Lm c:

Thnh tho x l kt qu quan st ca php o trc tip.

Thi gian thc hin: 2 tit

Phng tin m bo:

-My vi tnh 586;

-Phn mm MATLAB Version 5.2, MATHCAD 7 Professional.

1.1.Gii thiu chung 1. Phn mm MATLAB

Hin nay phn mm m phng MATLAB ngy cng c ng dng rng ri

trong nhiu lnh vc khoa hc cng ngh. Xt trn gc ng dng trong o

lng phn mm m phng ny mang tnh a nng cao. C th l:

-M phng c mu cc i lng nh th vin Sources (ngun mu) ca

Simulink;

-M phng c PT theo nguyn l xy dng khi ng dng cc phn t

chc nng c s c trong cc th vin Simulink, Blocksets and Toolboxes;

-Thay i c thi gian ly mu;

-Mun ho theo khi chc nng khi thc hin lnh Create Subsystem (To

h thng con);

-Trong th vin ca MATLAB c sn mt s c PT c m phng

nh my hin sng (Scope), my o s (Display), my v c tnh ( XY Graph)...

nn c th kim tra, so snh, o c tn hiu mi im trong s thit k;

-C th in s , th mt cch d dng v sao chp s sang dng vn

bn son tho Microsoft Word.

Cn c vo mc ch-yu cu t ra ta c th thit k m phng phn ln cc

ni dung th nghim - thc hnh o lng in - v tuyn in. y mt s phng tin o v khi chc nng c m phng t cc mch c s v c m

un ho.

2. Phn mm MATHCAD

Phn mm Mathcad c ng dng rng ri trong thc t tnh ton. Cch

lp trnh n gin, d sa li, kt qu nhn c rt trc quan. C th cho ng

thi di dng bng gi tr v th. C th in kt qu mt cch d dng v sao

chp chng sang dng vn bn son tho Microsoft Word.

Chng trnh t ng x l kt qu quan st ca php o trc tip v gin tip

c lp theo trnh t ng nh cc bc a ra trong gio trnh " o lng in-

v tuyn in":

-Nhp s liu v dy kt qu quan st, s ln quan st, xc sut tin cy, h s

Stiudent;

-Tnh gi tr trung bnh cng;

-Xc nh sai s d;

-Kim tra tng sai s d c bng 0 hay khng;

-Tm gi tr ca sai s bnh phng trung bnh ca kt qu quan st v ca gi

tr trung bnh cng;

-Kim tra cc trong dy kt qu quan st c sai s th hay khng; nu c th

ln quan st c sai s th b loi v qu trnh tnh ton c lp t u;

-Vit kt qu o.

Qu trnh x l kt qu quan st ca php o gin tip c thc hin thng

qua hai hoc mt s bc x l kt qu quan st ca cc php o trc tip v cui

cng l bc tnh kt qu chung.

1.2. cc bc tin hnh 1.2.1. M phng cc ni dung th nghim-thc hnh

Mc ch m phng cc ni dung th nghim-thc hnh gip cho hc vin

nm c mt cch khi qut nguyn l ca PT, cc phng php o s dng

trong hc phn th nghim-thc hnh o lng in-VT. Qu trnh m phng

c tin hnh theo cc bc sau y:

1.Bt ngun khi ng my

2.Gi chng trnh:

Stat Programs Matlab MALAB Command Window (Ca s) Open File Open/Bin (Ca s) ThiNghiem1 MATLAB Editor/ Debugger(Ca s) Tools Run ThiNghiem1(Ca s)

Trn ca s hin s m phng mch kim tra tham s ngun bng vn-

ampemt vn nng (Xem hnh 1-1).

3. Chy chng trnh

Vs220V

+

-

v

Vonm etm ot chieu

Vonm ethieu dung

+

-

v

V2

+

-

v

V1

Rt

Mux

Phan kenh1

77.17

18.39

0.18

HTS (V,V,A)

CM

In1

In2

Out1

Out2

CL cau C

BA nguon

+i-

Ampemet

Hinh 1-1 Kiem tra tham so nguon bang Von-ampemet van nang

ThiNghiem1(Ca s) Simulation Stat

Chng trnh c khi ng, sau khong thi gian t trc, kt qu cui

cng c hin th trn b hin th s (HTS). in p tng ng vi v tr di ca

chuyn mch CM l in p vo ca b chnh lu cu, khi ta bm p CM v tr

di v khi ng chng trnh th mn HTS hin gi tr in p ra b CL cu.

4. ng chng trnh

ThiNghiem1(Ca s) File Close Close/ThiNghiem1 (Ca s) No ( Ch :Khng ghi v lp theo tn mi ).

Lc ny chng trnh c ng, trn mn hnh hin ca s MALAB

Command Window. Cn lu rng mt s chng trnh ca s Close khng

xut hin.

5.Gi chng trnh tip theo

Thng thng gi chng trnh tip theo c nhanh chng ta cha cn

ng chng trnh trc , m dng ca s ca n gi chng trnh sau. V

d:

ThiNghiem1(Ca s) File Open Open/Bin (Ca s) ThiNghiem2 ThiNghiem2(Ca s)

Trn mn hnh nhn c ca s ThiNghiem2 (Xem hnh 1-2). Ta tin hnh

khi ng chng trnh theo cc bc nu trn nhn c kt qu m phng.

M ux

Phan kenh YY

Nguon t/h2 X

Nguon t/h1 YMan hinh

M HS21.537

KD3

1.939

KD2KENH LECH DUNG

1

KD1

1.27

2

CM quet

KENH LECH NGANG

CM dong bos

1

Bo tao quet

Hinh 1-2 Nghien cuu so do chuc nang cua MHS

Sau khi kt thc chng trnh nghin cu s chc nng MHS, ta ng mt

trong hai chng trnh v dng chng trnh cn li gi chng trnh th 3.

Nh vy ta c th gi ln lt 15 chng trnh m phng cc ni dung th

nghim-thc hnh o lng in-v tuyn in c sn trong ca s th mc

Open/Bin ca MATLAB. Cc chng trnh m phng c sp xp th t theo

tin trnh th nghim-thc hnh. C th l:

-Th nghim 1: Kim tra tham s ngun bng vn-ampemt vn nng;

-Th nghim 2: Nghin cu s chc nng MHS;

-Th nghim 3: Nghin cu ch qut ca MHS;

-Th nghim 4: Nghin cu ch ng b trong MHS;

-Th nghim 5: o gc lch pha dng MHS;

-Th nghim 6: o tn s dng MHS;

-Th nghim 7: o h s iu bin dng MHS;

-Th nghim 8: Nghin cu nguyn l xy dng vnmt tch phn 2 ln;

-Th nghim 9: Nghin cu nguyn l xy dng tnmt s;

-Th nghim 10: Nghin cu nguyn l xy dng my o chu k;

-Th nghim 11: Kim tra tn s my pht;

-Th nghim 12: o in tr, in dung ca t dng cu xoay chiu;

-Th nghim 13: o in tr, in dung bng my o s;

-Th nghim 14: o nng kh NO2 dng h thng o v cnh bo vi

sensor CTX-COX100;

-Th nghim 15: My o nhit loi hin s.

6. ng chng trnh m phng MATLAB

MALAB Command Window (Ca s) File Exit Matlab

Ch : Trc khi tt my vi tnh, tt c cc chng trnh ng dng u phi

ng li; Th t tt my: Stat Shut Down... Shut Down Window (Ca s) Yes Khi xut hin dng ch " It's now safe to turn off your computer '' th tt cng tc ngun.

1.2.2.T ng x l kt qu quan st ca php o

Qu trnh t ng x l kt qu quan st ca php o trc tip c thc hin theo chng trnh mu. V vy ta tin hnh cc thao tc sau y:

1. Bt ngun khi ng my( Nu my cha c khi ng)

2. Gi chng trnh Xuly1:

Stat Programs Mathsoft Apps Mathcad 7 Professional Mathcad Professional-[Untitled:1] (Ca s) Open Worksheet ( File Open...) Open/Mathcad (Ca s) Xuly1 Mathcad Professional-[Xuly1] (Ca s chng trnh X l 1)

Chng trnh X l 1-"T ng x l kt qu quan st ca php o trc tip"

c chy cho cc s liu ca php o a ra mc "I-SO LIEU VAO''(Xem kt

qu chy chng trnh 2 trang tip theo).

3. Nhp s liu mi:

Thay ton b s liu mi vo v tr s liu c mc "I-SO LIEU VAO". y

s ln quan st n khng hn ch; Xi - gi tr ln quan st i; tn,tn-1,...-h s Stiudent

ng vi ln quan st n, n-1,... vi xc xut tin cy Ptc.

Ch : Ch c php thay s liu bng s mc "I-SO LIEU VAO", gi s cc s liu nhn c t php o lp li.

4.Chy chng trnh:

Sau khi kt thc nhp s liu chung trnh c chy t ng v cho ra kt

qu. Theo kt qu chy ca chng trnh mu, ln quan st th 5 c sai s th, n

c loi b cc bc x l lt li.

5. Th chng trnh theo s liu mi:

cho n gin ta thay i tr s ln quan st th nht X1=5.2 gi s

X1=5.55. Kt qu nhn c: 2 kt qu quan st c sai s th l X1 v X5.

6. ng chng trnh:

Mathcad Professional-[Xuly1] (Ca s) File Close Mathcad (Ca s) No

Ch : Khi ng chng trnh khng ghi li chng trinh theo s liu mi v khng lp chng trnh theo tn mi.

TU DONG XU LY KET QUA QUAN SAT CUA PHEP DO TRUC TIEP

I- SO LIEU VAO ( tn ung voi n ): n 6 i 1 2 nX 1 5.2 X 2 5.0 X 3 4.7 X 4 4.9 X 5 4.3 X 6 5.1

Ptc 0.80 tn

1.476 tn 1 1.533 t n 2 1.638 t n 3 1.886

II- TINH KET QUA:

1.Tinh gia tri trung binhA

1

n

i

X in

=

A 4.867

2.Tinh sai so du i X i A i

0.3330.133

0.1670.0330.567

0.233

3.Kiem tra

1

n

i

i=

2.665 10 15

4. Tinh sai so bptb cua ket qua quan sat

S 1

n

i

i2

=

n 1S 0.327 S

nt

nS S

n0.482

5. Kiem tra sai so tho: Sn - I i I > 0 ---khong c o s s th o S n - I i I < 0 ------ c o s s th o

i

123456

X i5.2

54.74.94.35.1

i S n i i0.1490.3490.3150.449

0.0850.249

Y i X i i 0if

0 otherwise

Y i5.2

54.74.9

05.1

X i 1 i 0if

0 otherwise

X i111101

III- XAC DINH SO LAN QUAN SAT m KHI CO SAI SO THO

m n

1

n

i

X i=

nif

n 1( )1

n

i

X i=

n 1if

n 2( )1

n

i

X i=

n 2if

n 3( )1

n

i

X i=

n 3if

n 4( ) otherwise

m 5

t tn

m nif

tn 1 m n 1if

tn 2 m n 2if

tn 3 m n 3if

t 1.533

IV- TINH LAI KET QUA

1.Tinh gia tri trung binh B1

n

i

Yim

=

B 4.98

2. Tinh sai so du

i Yi B i0.220.02

0.280.084.98

0.12

Yi Yi i 0.5 Bif

B otherwise

Yi5.25

4.74.94.985.1

i Yi B i0.220.02

0.280.080

0.12

3. Tinh sai so bptb cua ket qua quan sat lan 2

S 1

n

i

i2

=

m 1S 0.192 S

mt S S

m0.295

V- KET QUA X B X 4.98 Sai so nn: nn

Sm

m

nn 0.132 Ptc 0.8 Phan bo Stiudent

Qu trnh t ng x l kt qu quan st ca php o gin tip c thc hin theo chng trnh mu. V vy ta tin hnh cc thao tc sau y:

1/ Gi chng trnh Xuly2:

Mathcad Professional -[Untitled:1] (Ca s) Open Worksheet (File Open...) Open/Mathcad (Ca s) Xuly2 Mathcad Professional-[Xuly2] (Ca s chng trnh X l 2)

Chng trnh X l 2-"T ng x l kt qu quan st ca php o gin tip"

c chy cho cc s liu ca php o a ra mc "I-SO LIEU VAO''.

2/ Nhp s liu mi:

Thay ton b s liu mi vo v tr s liu c mc "I-SO LIEU VAO". y s ln quan st n khng hn ch; Xi - gi tr ln quan st i ca i lng x; Yi

- ga tr ln quan st i ca php o i lng y; t1, t2, ... -h s Stiudent ng vi

ln quan st n, n-1,... vi xc xut tin cy Ptc; f(x,y) = ... - quan h hm gia v y.

Ch : Ch c php thay s liu bng s nhn c t php o lp li mc "I-SO LIEU VAO", tr hm f(x,y).

3/ Chy chng trnh:

Sau khi kt thc nhp s liu, chung trnh c chy t ng v cho ra kt

qu.

4/ ng chng trnh v kt thc:

Mathcad Professional-[Xuly2] (Ca s) File Exit Mathcad (Ca s) No

Ch : Khi ng chng trnh khng ghi li chng trinh theo s liu mi v khng lp chng trnh theo tn mi.

5/ Tt my theo trnh t:

-Tt c cc chng trnh ng dng u phi ng li;

-Th t tt my: Stat Shut Down... Shut Down Window (Ca s) Yes Khi xut hin dng ch " It's now safe to turn off your computer '' th tt cng tc ngun.

Bo co kt qu:

-Bo co kt qu 8 bi th nghim-thc hnh vit theo mu ph lc 3;

-Ni dung bo co bi 1: X l mt trong cc dy kt qu quan st theo s

liu a ra bmg 1-1 ( Tng hc vin thc hin c lp ngoi gi, nhm th

nghim-thc hnh cng trao i thng nht bo co chung).

Bng 1-1

in p Ux (V) TT

1 2 3 4 5 6

Ptc

1 5,2 5,6 4,9 5,1 5,0 5,1 0,80

2 6,3 6,2 5,5 6,1 6,3 6,4 0.80

3 7,0 7,1 6,9 7,1 7,2 7,0 0,80

4 8,2 8,0 8,1 8,7 8,1 7,9 0,80

5 9,5 9,3 9,4 9,3 9,5 9,4 0,80

6 10,0 9,9 10,1 10,2 9,4 10,0 0,80

Bi 2

S dng my hin sng trong o lng

Mc ch - yu cu:


Hiu c:

- S chc nng v cc ch lm vic c bn ca my hin sng (MHS);

- Cc phng php o dng MHS.

Lm c:

S dng thnh tho MHS theo chc nng hin th dng tn hiu v o cc

tham s ca tn hiu: bin , tn s, chu k, rng xung, gc lch pha, h s

iu bin.


Phng tin m bo:

- My hin sng: LS 1020, LS 1040, HM 303-4, HM 1007;

- My pht o lng: 27A, 17A;

- Panel mch dch pha RC. 2.1. Gii thiu chung

My hin sng l mt phng tin o vn nng, dng quan st dng tn

hiu v o cc tham s ca tn hiu. MHS c s dng rt rng ri trong o

lng, c dng ch yu quan st dng tn hiu thay i theo thi gian, o

cc tham s nh in p, tn s, gc lch pha, mo, su iu ch...

V cu to MHS c xy dng t 4 khi c bn:

- ng tia in t;

- Tuyn lch ng (Tuyn Y);

- Tuyn lch ngang ( Tuyn X-To qut);

- Khi ngun.

Thng thng hin nay ngi ta ch to MHS hai hoc nhiu knh vi tuyn

lch ng c hai hoc nhiu u vo. Vi kt cu ny ta c th quan st ng thi

nhiu tn hiu khc nhau trong cng mt thi im. My hin sng thng dng

kt hp vi b bin i hot nghim, m rng c di tn o c. Nu s dng

ng tia in t c lu nh cao, ta c th to c MHS c nh, nh ca tn

hiu c lu gi trong mt khong thi gian nht nh v c ti hin thi

im cn thit.

Theo xu th pht trin ca khoa hc v cng ngh, hin nay c nhiu loi

my hin sng s c ch to, dn dn thay th mt phn MHS tng t. MHS

s xy dng theo nguyn l bin i tn hiu tng t v dng s vi mc ch x

l, lu gi ri li c bin i tip v dng tng t hin th trn mn hnh.

My hin sng s ngoi vic hin th dng tn hiu lin tc cn lu gi, hin th

gi tr cc tham s dng ch s trn mn hnh.

Mc d my hin sng s l xu hng pht trin, nhng MHS tng t vn

c dng rt ph bin, v n d s dng, gi thnh r, cc ch tiu k thut vn

p ng c nhu cu thc t. Chnh v vy mc tiu ca bi th nghim-thc

hnh l khai thc s dng MHS tng t. S chc nng, nguyn l qut v

ng b, cc ch lm vic ca MHS tng t c gii thiu ni dung bi

thc hnh 1 v c th tham kho gio trnh [ 1 ].

s dng c hiu qu MHS cn nm chc cc ch lm vic c bn ca

my hin sng.

Ch qut lin tc ng b trong

y l ch c s dng rng ri nht nhm quan st dng tn hiu iu

ho hoc xung tun hon c hng khng ln; o bin , tn s, chu k,

su iu bin. ch ny in p qut l hm lin tc theo thi gian dng rng

ca, cn tn hiu ng b ly t ngun tn hiu cn nghin cu thng qua knh

lch ng.

Ch qut lin tc ng b ngoi

Ch qut lin tc ng b ngoi cng dng quan st tn hiu iu ho.

Ch ny l bt buc khi o gc lch pha theo phng php nhn dng tn hiu

dng MHS hai knh c 2 u vo X1, X2 vi 2 u vo ng b ring r. ch

ny tn hiu ng b ly t ngoi thng qua u vo X hoc u vo ng b.

Ch qut i ng b trong

Ch ny dng nghin cu dng tn hiu khng tun hon vi im xut

pht qut thay i ph hp vi quy lut ca tn hiu, hoc dng nghin cu

xung c hng ln vi rng qut ln hn khng nhiu so vi rng xung.

Ch khuch i

Ch khuch i (Cn gi l ch X-Y) dng v c tuyn hoc tin hnh mt s php o nh o gc lch pha, o tn s, o iu ch...MHS ch ny cn c s dng lm ch th cn bng cho mt s php o so snh. Theo nguyn l bin i MHS lm vic theo 2 knh c lp, b to qut rng ca c ngt ra khi qu trnh hot ng.

2.2. cc bc tin hnh 2.2.1- Nghin cu s dng MHS

1 c tnh k thut ca MHS

My hin sng LS 1020: (Hng LEADER ch to)

- Mn hnh 6 inch ;

-Di tn ti 20 MHz;

-Ch lm vic: Mt knh (CH1 hoc CH2), hai knh (CH1 v CH2) v ch

X-Y (X-CH1, Y-CH2);

-H s lch ng: 0,5 mV/vch - 5 V/vch;

-H s qut: 0,1 s/vch - 0,2 s/vch;

-B hiu chun: in p ra 0,5 Vp-p 2, tn s 1kHz, xung vung.

My hin sng LS 1040: (Hng LEADER ch to)

-Mn hnh 6 inch ;

-Di tn ti 40 MHz;

-Ch lm vic: Mt knh (CH1 hoc CH2), hai knh (CH1 v CH2),ba

knh (CH1, CH2 v CH3 or EXT) v ch X-Y (X-CH1 v Y-CH2; X-CH3,

Y1-CH1 v Y2-CH2);

-H s lch ng: 5 mV/vch - 5 V/vch -knh CH1, CH2;

-H s lch ng: 0,1V/vch , 0,5 V/vch -knh CH3;


-B hiu chun: in p ra 0,5 Vp-p 2, tn s 1kHz, xung vung.

My hin sng HM 303-4: (Hng HAMEG ch to)

-Mn hnh 6 inch ;

-Di tn ti 30 MHz;

-Ch lm vic: Mt knh (CH I hoc CH II), hai knh (CH I v CH II) v

ch X-Y (X-CH II v Y-CH I);

-H s lch ng: 5 mV/vch - 20 V/vch;


-B hiu chun:in p ra 0,2V1% v 2V,tn s 1kHz/1MHz, xung vung.

My hin sng tng t-s HM 1007: (Hng HAMEG ch to)

-Mn hnh 6 inch ;

-Di tn ti 100 MHz;

-Ch lm vic: Mt knh (CH I hoc CH II), hai knh (CH I v CH II) v

ch X-Y (X-CH II v Y-CH I);

-H s lch ng: 5 mV/vch - 20 V/vch ( 3%);

-H s qut (tng t ): 0,05 s/cm - 1 s/cm( 3%);

-H s qut (s ): 50 s/vch - 50 ms/vch ( 3%);

-B nh: 2k x 8 bit;

-B hiu chun: /a 0,2 V/ 2 V 1% , xung vung 1kHz/1MHz .

2. Chc nng cc phn t trn mt MHS (Xem bng 2-1, 2-2, 2-3)

Bng 2-1 Mn hnh

K hiu cc phn t

LS 1020

LS 1040

HM 303-4

HM 1007

Chc nng, nhim v

(1) (2) (3)

POWER on/off POWER on/off Cng tc ngun

INTEN INTENS Chit p iu chnh sng tia

FOCUS FOCUS Chit p iu chnh hi t tia

ILLUM ILLUM Chuyn mch thay i chiu

sng mn hnh

ROTATION TR Chit p cn chnh nh

GND Cc u t

Bng 2-2 Knh lch ng

K hiu cc phn t

LS 1020 LS1040

HM 303-4 HM 1007

Chc nng, nhim v

(1) (2) (3)

CH1

POSITION

Y-POS.I,

Y-POS.II

Chit p chuyn dch tia Y1(LS 1020,1040), 2

tia (HM 303-4, 1007)

CH2

POSITION,

PULL CH2

INV

Chit p chuyn dch tia Y2 ko nm, tn hiu

Y2 o pha

VOLTS/DIV VOLTS/DIV Chuyn mch h s lch ng (V/ vch)

(1) (2) (3)

VARIABLE

PULLx10

MAG

Chit p ng tm vi chuyn mch VOLTS/

DIV dng tinh chnh h s lch ng, v tr

kch tri ca n (CAL) l v tr o in p. Nm

chit p ko ln, nh theo trc Y ko dn 10 ln

Y MAG.x5 Phm n, ko dn nh theo trc Y 5 ln

VAR 2.5:1 Chit p ng tm vi chuyn

mchVOLTS/DIV dng tinh chnh h s lch

ng,v tr kch tri ca n (CAL) l v tr o

in p

AC GND

DC

GD AC DC Chuyn mch dng tn hiu vo: AC-xoay

chiu, GND (GD)- t, DC-mt chiu

CH1 or X in

CH2 or Y in

INPUT;

INPUT CH I

INPUT CH II

Cc u vo knh Y hoc cc u vo X, Y

ch X-Y

V-MOD:

-CH1

-

-CH2

-

-CHOP

-

-ALT

-

-ADD

VERT.MOD:

-CHI/II-

TRG.I/II-

-CHI/II-

TRG.I/II

-CHOP

-

-ALT

-

-ADD

Chn ch hin th cho knh lch ng:

-Hin nh tn hiu knh Y1 (v tr CH1, phm

CHI/II-TRG.I/II nh)

-Hin nh tn hiu knh Y2 (v tr CH2, phm

CHI/II-TRG.I/II n)

-Hin nh c 2 knh Y1, Y2 theo ch xen k

vi h s qut trn 0,5 ms/vch

-Hin nh c 2 knh Y1, Y2 theo ch ln

lt vi h s qut di 0,5 ms/vch

-Hin tn hiu tng ca 2 knh Y

Ch : i vi MHS HM 303-4, HM 1007 ch

hin th cng l ch ng b

(1) (2) (3)

CAL0.5Vp-p 0.2V-2V,

CAL.1kHz/

1MHz

u ra ngun in p, tn s chun

LS 1040:

-TRIPLE

(CH3)

-CH3 POS

-Phm n to knh Y3 vi u vo CH3 or EXT

(CH3 chung vi u vo ng b)

-Chit p chuyn dch theo trc Y ca knh 3

OVER SCAN n hin th v tr tia ngoi mn hnh theo trc

Y

REF. POS.

(HM 1007)

Chit p tm tia

Bng 2- 3 Knh to qut

K hiu cc phn t

LS 1020 LS 1040

HM 303-4 HM 1007

Chc nng, nhim v

(1) (2) (3)

TEME/DIV TEME/DIV Chuyn mch thay i h s qut (s/vch, ms/vch, s/vch) vi chit p ng tm tinh

chnh h s qut, v tr kch tri ca n l v

tr o tham s thi gian (CAL)

TEME

VARIABLE (LS

1020)

Chit p tinh chnh h s qut, v tr kch

tri (CAL) -o tham s thi gian

H-POSITION X-POS. Chit p chuyn dch tia theo trc X

PULLx10 MAG X-MAG x10 Nm chit p H-POSITION ko ra ( Phm

n) ko dn ng qut 10 ln

(1) (2) (3)

EXT

TRIGNPUT

TRIG. INP. u vo ng b

HOLD OFF HOLD OFF Chit p iu chnh ng b tn hiu gin

on

PULL NORM/

AUTO

AUTO/NORM

AT/NORM

Nm ng tm chit p HOLDOFF: n vo

-ng b thng, ko ra- ng b t ng

(phm nh-t ng, phm n-thng)

COULING:

-AC

-

-HF-REJ

-DC

-TV-V,TV-H

TRIG.:

-AC

-

-HF-REJ

-DC

-TV-V,TV-H

Chuyn mch dng tn hiu ng b:

-Tn hiu xoay chiu ln hn 10 Hz (ch

thng thng)

-Tn hiu di 100 kHz

-Tn hiu di 10 Hz k c t/h mt chiu

-Tn hiu TV

-in li

SLOPE+/-, TV

POL, LEVEL

LEVEL,

SLOPE/

LEVEL

Chn cc tnh tn hiu ng b v iu

chnh pha ca nh

LS 1020:

-TEME/DIV-

XY -

-Z AXIS INPUT

-SOURCE

-Ch X-Y vch kch phi ca chuyn

mch TEME/DIV, y CH1-X-u vo

knh X, CH2-Y-u v knh Y

-u vo Z (Mt sau my)

-Chuyn mch ngun ng b c thit

lp v tr tng ng vi v tr ca chuyn

mch

V-MOD

LS 1040:

HORIZ DELAY

A ALT B:

-A+ALT

-ALT+B

-SOURCE

Gi chm knh lch ngang -

-Hai phm A v ALT cng n to ch X-

Y (CH1-X, CH2-Y)

-Hai phm ALT v B cng n to ch X-

Y theo 2 knh (CH3-X, CH1-Y1 v CH3-X,

CH2-Y2)

-Chuyn mch ngun ng b c thit

lp v tr tng ng vi v tr ca chuyn

mch

V-MOD

X-Y Phm n to ch X-Y (CH I-Y, CH II-X)

2.2.2- Nghin cu s dng my pht o lng

1. My pht tn hiu sin v xung vung 27A (Hng LEADER ch to)

c tnh k thut:

-Di tn t 10 Hz n 1 MHz vi 5 bng tn

-Sai s: (5% + 2 Hz) [10 Hz - 1 MHz]

(3% + 2 Hz) [100 Hz - 100 kHz]

-Tr khng ra: 600

-Tn hiu sin u ra t 10 Hz n 1 MHz, in p 5 V vi sai s:

di 0,5 %, 200 Hz - 100kHz

di 1%, 100 Hz - 500kHz

di 2 %, 10 Hz - 1MHz

-Tn hiu xung t 10 Hz n 100 kHz, in p 5 V

-C u vo ng b.

Cch ly tn hiu ra:

- Thit lp cng tc WAVEFORM v tr tn hiu sin hoc xung vung theo

yu cu;

-Thit lp cng tc HIGH-LOW v tr tu thuc vo mc suy gim tn hiu,

v tr LOW tng ng vi mc suy gim 1/10 (40dB);

- Thit lp tn s nh chuyn mch FREQ. RANGE v nm xoay

FREQUENCY;

- Bt cng tc ngun POWER;

- iu chnh nm FINE ta nhn c u ra OUPUT dng tn hiu vi tn

s v mc in p theo yu cu.

2. My pht tn hiu cao tn 17A (Hng LEADER ch to)

c tnh k thut:

- Di tn 100 kHz -100 MHz vi 6 bng tn:A-B-C-D-E-F vi u ra RF

- Sai s: 3 %

- Tn hiu iu trong 1 kHz 30 %, iu ch ngoi t 50 Hz n 20 kHz

- Tn hiu u ra tn thp (Audio) : 1 kHz, 1V v ln hn.

Cch ly tn hiu cao tn u ra RF OUTPUT:

- Thit lp cng tc HIGH-LOW v tr tu thuc vo mc suy gim tn

hiu, v tr LOW tng ng vi mc suy gim 1/10 (40dB);

-Thit lp tn s nh chuyn mch FREQ. RANGE v nm xoay

FREQUENCY;

-Bt cng tc ngun POWER;

-iu chnh nm FINE ta nhn c u ra OUPUT dng tn hiu vi tn

s v mc in p theo yu cu.

Tn hiu m tn 1 kHz ly u ra Audio OUTPUT.

Cch ly tn hiu iu bin u ra OUTPUT:

-Thit lp cng tc HIGH-LOW v tr tu thuc vo mc suy gim tn hiu,

v tr LOW tng ng vi mc suy gim 1/10 (40dB);

-Thit lp tn s cao tn nh chuyn mch FREQ. RANGE v nm xoay

FREQUENCY;

-Thit lp tn hiu iu ch:

iu ch trong 1 kHz chuyn mch MOD MODULATION t v tr IN

MOD;

iu ch ngoi chuyn mch MOD MODULATION t v tr EXT MOD

khi a tn hiu iu ch ngoi ti u INPUT-OUTPUT;

-Bt cng tc ngun POWER;

-iu chnh bin tn hiu iu ch ngoi, ta nhn c u ra OUPUT

dng tn hiu iu bin theo yu cu.

2.2.3.Cc php o dng MHS

Ch : K hiu ngoi du ngoc dng cho MHS LS 1020 v LS 1040, k hiu trong ngoc dng cho MHS HM 303-4 v HM 1007; nu khng c du ngoc th k hiu dng chung cho c 4 loi my.

1.Chun b lm vic

a/ Khi hin th:

- Chuyn mch ILLUM t v tr mong mun;

- Nm iu chnh FOCUS xoay v tr trung gian;

- Nm iu chnh INTEN (INTENS) xoay v tr trung gian.

b/ Khi lch ng:

- Chuyn mch V-MOD (VERT. MOD) t v tr ALT (Phm ADD-n hoc

2 phm DUAL, ADD cng n);

- Hai chuyn mch VOLTS/DIV t v tr 0.1 V;

- Hai nm VARIABLE (VAR 2.5:1) n xung v xoay v v tr CAL (xoay

v v tr CAL) (Hai phm Y MAG x5 v tr nh);

- Hai nm CH1, CH2 POSITION ( Y-POS.I, Y-POS.II) xoay v v tr trung

gian;

-Hai chuyn mch AC- GND-DC ( GD AC-DC) t AC (Phm AC-DC nh)

c/ khi to qut:

- Chuyn mch TEME/DIV v tr 0.5 ms;

-Nm TEME VARIABLE xoay v v tr CAL (Nm ng tm vi chuyn

mch TEME/DIV xoay v v tr CAL);

-Nm H POSITION ( X-POS.) n vo v xoay v v tr trung gian (xoay v v

tr trung gian );

d/ Khi ng b;

- Nm SLOPE xoay v "+" (Phm SLOPE nh);

- Nm LEVEL xoay v v tr trung gian;

- Nm PULL NORM/ AUTO v tr n (NORM);

-Chuyn mch SOURCE t v tr CH1 ( i v MHS HM 303-4, HM

1007 ngun ng b c thit lp t ng theo v tr chuyn mch VERT.-

MOD);

-Chuyn mch COUPLING (TRIG.) t v tr AC.

e/ Cp ngun v hiu chnh:

-n phm cng tc ngun POWER, n bo ngun sng v 2 tia c hin trn mn hnh l 2 ng thng song song theo phng nm ngang;

- iu chnh cc nm FOCUS, INTEN cc tia c r nt v sng cn

thit;

- Dng nm H POSITION ( X-POS.) a cc tia theo truc X v v tr trung

tm ca mn hnh;

-Dng nm CH1, CH2 POSITION ( Y-POS. CH.I, CH.II ) a cc tia theo

trc Y ti ng trung tm mn hnh.

Ch : MHS HM 303-4, HM 1007 c n OVER-SCAN, bo v tr tia nm

ngoi mn hnh theo trc Y; chit p tm tia REF. POS. c HM 1007.

f/ Ni ngun tn hiu vi MHS

Ngun tn hiu c ni vi cc u vo MHS bng cp thng, cp ng

trc hoc u o in dung thp: Cp thng dng trong trng hp mc tn hiu

cao, tn s di 100 kHz; cp ng trc c s dng khi ngun tn hiu c u

ni cp dng ny; u o in dung thp c mc nhn 1 (x1) v nhn 10 (x10),

c s dng tn s cao, gim c nh hng ca nhiu v khng cn u t

thit b th.

kim tra, hiu chnh h s lch ng v h s qut ta thc hin cc thao

tc sau y:

-Ni u ra CAL 0.5Vp-p (0.2V-2V, CAL.1kHz/ 1MHz- Ni u 0.2V, phm

CAL nh) vi u vo CH1 or X in ( INPUT, INPUT CH.I ), sau khi iu chnh

nh nm CH1 POSITION ( Y-POS. CH.II ) ta phi nhn c trn mn hnh tia

th nht dng xung vung c bin l 5 vch, chu k l 2 vch ( Bin - 2

vch, chu k - 2 vch ). Tia th 2 l ng thng trng vi trc X trung tm;

-Nu ta ni u ra CAL 0.5Vp-p (0.2V-2V, CAL.1kHz/ 1MHz- Ni u

0.2V, phm CAL nh) vi u vo CH2 or X in ( INPUT, INPUT CH.II ), ta nhn

c tia th 2 l dng xung tng t, cn tia th nht l ng thng.

Trn hnh 2.1 a ra dng xung trn mn MHS LS 1020 khi ni u CAL

0.5Vp-p vi u CH1 or X in.

Hnh 2.1

-c s vch theo chiu cao ca nh v tnh bin xung:

Um = Ky( V/vch) x Ny (vch) , V

y Ky - h s lch ng, Ny - s vch theo chiu cao ca nh

Um = 0,1 (V/vch) x 5 (vch) = 0,5 V

-Nm H POSITION ( X-POS.) xoay v v tr nh nm trung tm mn

hnh, i qua cc im ng li Y ct trc trung tm X (Xem hnh 2.1);

-oc s vch tng ng vi mt chu k tn hiu tnh t im ct, xc nh tn

s thng qua chu k:

F= 1/T =1 / [Kx (s/ vch, ms /vch, s/vch) x Nx(vch)] , MHz, kHz, Hz

y Kx - h s qut, Nx - s vch tng ng vi mt chu k nh.

F = 0,5 (ms/vch) x 2 (vch) = 1 kHz.

Kt qu thu nhn:

-Chng loi MHS s dng;

-V dng xung theo hin th ca mn hnh;

-Kt lun v chnh xc xc lp h s lch ng vch 0,1V, h s qut

vch 0,5 ms.

Sau khi kt thc bc chun b ta ngt cp o v gi nguyn cc v tr cc

nm, nt v c cu iu khin ca MHS v tt cng tc ngun.

2. o in p , tn s v rng sn xung, h s iu bin s dng ch mt tia

a/ Bc hiu chnh

Thng thng knh CH1 ( CH.I ) c s dng ch ny. Cc bc hiu

chnh nhn chung ging nh mc 1 phn 2.2.3 v thc hin cc thao tc b xung:

-Chuyn mch V-MOD (VERT. MOD) t v tr CH1 (phm CH I/II- nh);

-Chuyn mch VOLTS/DIV t v tr 5V;

-Nm VARIABLE (VAR 2.5:1) n xung v xoay v v tr CAL (xoay v v

tr CAL) (Phm Y MAG x5 v tr nh);

-Chuyn mch TEME/DIV v tr 1 ms;



-Chuyn mch SOURCE t v tr CH1 ( i vi MHS HM 303-4, HM

1007 ngun ng b c thit lp t ng theo chuyn mch VERT. MOD).

Nh vy ta thit lp MHS ch qut lin tc ng b trong.

b/ o in p, tn s tn hiu iu ho

-a tn hiu t u ra my pht 27A (Thit lp ch dng hnh sin) ti

u vo CH1 or X in ( INPUT, INPUT CH.I ) ca MHS;

-Bt cng tc ngun MHS;

-Chuyn mch AC- GND-DC ( GD AC-DC) t AC (Phm AC-DC nh);

-Chuyn mch VOLTS/DIV t v tr thch hp ca nh ln;

-Chuyn mch TEME/DIV t v tr thch hp nh hin mt hoc hai

chu k;

-Nm CH1 POSITION ( Y-POS.I ) xoay v v tr im cc tiu ca nh

nm trn vch ngang di cng ( Xem hnh 2.2);

-c s vch theo chiu cao ca nh v tnh gi tr hiu dng ca in p

hnh sin : U = [ Ky( V/vch) x Ny (vch)] / 2,83 , V

-Nm H POSITION ( X-POS.) xoay v v tr nh nm trung tm mn

hnh, i qua mt trong cc im li Y ct trc trung tm X (Xem hnh 2.3);

-oc s vch tng ng vi mt chu k tn hiu tnh t im ct, xc nh tn

s thng qua chu k:

F= 1/T =1 / [Kx (s/ vch, ms /vch, s/vch) x Nx(vch)], MHz, kHz, Hz

Kt qu thu nhn:

-V dng nh theo hin th ca mn hnh ;

-Ghi cc gi tr Ky, Kx, Ny, Nx v tnh gi tr hiu dng ca in p v tn

s tn hiu cho 3 trng hp F = 10 kHz, 50 kHz, 100 kHz;

-nh gi v kt qu nhn c v so snh n cc gi tr tn s c thit lp

trn my pht.

Hnh 2.2

Hnh 2.3

c/ o rng sn xumg

rng sn xung l khong thi gian gia mc 10 % v 90 % bin

xung. Ta iu chnh sao cho nh v y xung nm trn hai ng trung gian

(0% v 100%) cch ng trung tm 2,5 vch v 2 pha. rng xung c xc

nh thng qua rng gia 2 im ct ca nh vi 2 ng li ( 10% v 90%) ,

cch ng trung tm X 2 vch (xem hnh 2.4).

iu chnh MHS theo mc1 phn 2.2.3 v thc hin cc thao tc tip theo:

-My pht 27A thit lp ch pht xung tn s cc i 100 kHz;

-a tn hiu t u ra my pht ti u vo CH1 or X in ( INPUT, INPUT

CH.I ) ca MHS;

-Thit lp mt hoc hai chu k nh nh chuyn mch TEME/DIV;



-iu chnh bin xung l 5 vch bng chuyn mch VOLT/DIV v chit

p VARIABLE (VAR 2.5:1) ;

-y ca xung a ti ng 0% nh nm CH1 POSITION ( Y-POS.I), lc

ny nh xung trng vi ng 100%;

-a sn trc (sau) ca xung trng vi ng Y trung tm nh nm

H-POSITION (X-POS );

-Nm H-POSITION PULLx10 MAG (X-MAG x10) ko ln (Phm n

xung), nh c ko dn ra 10 ln theo trc X (Xem hnh 2.4);

- rng sn xung Tsx c xc nh theo cng thc:

Tsx = Kx. Nsx . 0,1 , s (ms, s)

y Nsx - s vch theo trc X gia 2 im 10% v 90% bin xung. Theo

hnh 2.4 Hsx = 1,8 vch.

100%

90 %

10%

0%

Hnh 2.4

Kt qu thu nhn:


-Ghi cc gi tr Kx, Nsx v tnh rng sn xung Tsx tn s 100kHz;

-nh gi v cht lng my pht ch pht xung tn s 100kHz.

d/ o h s iu bin

-a tn hiu t u ra my pht 17A (Thit lp ch iu ch trong ) ti

u vo CH1 or X in ( INPUT, INPUT CH.I ) ca MHS;

-Chuyn mch AC- GND-DC ( GD AC-DC) t AC (Phm AC-DC nh);

-Chuyn mch VOLTS/DIV t v tr thch hp chiu cao ca nh

ln;

-Nm CH1 POSITION ( Y-POS.I ) xoay v v tr nh nm trung tm mn

hnh;

-Chuyn mch TEME/DIV v tr thch hp nh hin hai hoc mt vi chu

k tn hiu iu ch;

-Nm VARIABLE (VAR 2.5:1) n xung v xoay (xoay) v v tr nh c

im cc i ca bin trn v im cc tiu ca bin di nm trn 2 ng li

i xng (Xem hnh 2.5);

-c s vch theo chiu cao ca nh Na tnh t im cc i bin trn n

im cc tiu bin di, Na ly ti 1 ch s sau du phy;

-c s vch theo chiu cao ca nh Nb tnh t im cc tiu bin trn n

im cc i bin di, Nb ly ti 1 ch s sau du phy;

-Tnh h s iu bin m theo cng thc:

m = 100.(Na - Nb)/(Na + Nb) , %

Theo hnh 2.5 Na = 6,0 vch, Nb =2.0 vch , m = 50 %.

Hnh 2.5

Kt qu thu nhn:


-Ghi cc gi tr Na, Nb v tnh h s iu bin trong ca my pht 17A.

3.o gc lch pha s dng ch hai tia

a/ Bc chun b

ch ny ta c th cho hin th mt trong 2 tia hoc c 2 tia nh chuyn mch V-MOD (VERT. MOD). Cc bc hiu chnh nhn chung ging nh mc

3.1 v thc hin cc thao tc b xung sau y:

-Chuyn mch V-MOD (VERT. MOD) t v tr ALT cho tn s cao,

CHOP cho tn s thp (Phm ADD-n hoc 2 phm DUAL, ADD cng n);

-Hai chuyn mch AC-GND-DC ( GD AC-DC) t AC (Phm AC-DC nh);

-Hai nm VARIABLE n xung (Phm Y MAG x5 v tr nh);

-Chuyn mch SOURCE t v tr CH1 (i vI MHS HM 303-4,HM 1007

ngun ng b c thit lp t ng theo v tr chuyn mch VERT.-MOD);

-Chuyn mch COUPLING (TRIG.) t v tr AC.

b/ o gc lch pha (Xem mch o hnh 2.6)

-a tn hiu t u ra my pht 27A ti u vo CH1 or X in (INPUT,

INPUT CH.I) ca MHS;

-a tn hiu t u ra my pht 27A ti u vo mch dch pha RC, tn hiu

t u ra ca mch dch pha a ti u vo CH2 or Y in (INPUT, INPUT CH.II )

ca MHS;

-Thit lp my pht ch sin vi tn s trong khong 4-10 kHz ( tn s

ny in p ra b dch pha t b suy gim);

U'2 1

U''2 2

U'''2 3

Hnh 2.6

-Bt ngun MHS v my pht, ta nhn c nh 2 tn hiu trn mn hnh;

-Nm CH1 POSITION ( Y-POS.I ) xoay v v tr tia nm trung tm mn

hnh;

-Bt 2 chuyn mch VOLTS/DIV v xoay 2 nm VARIABLE (VAR 2.5:1)

ti v tr thch hp chiu cao ca 2 tia khong 4 - 5 vch;

-Bt chuyn mch TEME/DIV v xoay nm TEME VARIABLE (VAR

2.5:1) ti v tr thch hp nhn c chu k nh bng 8 vch (mi vch ng vi

gc lch pha 45O ) ;

-Xoay nm H-POSITION (X-POS ) tia th nht ct tm im ca mn

hnh, nh nhn c c dng nh hnh 2.7;

MHS Y1 Y2

Dch pha RC

Mypht 27A

-c s vch N tng ng vi gc lch pha , tnh tri s theo cng thc:

= 360O. N / 8 = 45O. N

Hnh 2.7

Kt qu thu nhn:

Xc nh gc lch pha cho 3 trng hp: u vo CH2 or Y in (INPUT,

INPUT CH.II ) ca MHS ni ln lt vi cc u ra 1, 2, 3 ca b dch pha RC

cng mt tn s;

4. o gc lch pha, tn s s dng ch X-Y

y l ch khuch i, nh nhn c trn mn hnh MHS l hnh Lixazu.

Cc bc hiu chnh mn hnh v khi lch ng nhn chung ging nh mc1

phn 2.2.3.

a/ o gc lch pha

-a chuyn mch TEME/DIV v v tr kch phi X-Y i vi MHS LS1020,

n ng thi 2 phm A v ALT ca khi HORIZ DELAY i vi MHS LS 1040,

-n phm X-Y i vi MHS HM 303-4 v HM 1007;

-a tn hiu t u ra my pht 27A ti u vo CH1 or X in (INPUT,

INPUT CH.II ) ca MHS;

-a tn hiu t u ra my pht 27A ti u vo mch dch pha RC, tn hiu

t u ra ca mch dch pha a ti u vo CH2 or Y in (INPUT, INPUT CH.I )

ca MHS;

-Thit lp my pht ch sin vi tn s trong khong 4-10 kHz ( tn s

ny in p ra b dch pha t b suy gim),

Mch o gc lch pha ging nh mch hnh 2.6;

-Chuyn mch CH1 AC-GND-DC ( CH.II GD AC-DC) t AC (Phm AC-

DC nh);

-Chuyn mch CH2 AC-GND-DC ( CH.I GD AC-DC) t GND (Phm

GD n);

-Thay i v tr chuyn mch CH1 (CH.II) VOLT/DIV v iu chnh nm

VARIABLE di tia theo trc X l 6 vch;

-Chuyn dch tia v trung tm mn hnh nh nm CH1-POSITION ( Y-

POS.II);

-Chuyn mch CH1 AC-GND-DC ( CH.II GD AC-DC ) t GND (Phm

GD n);

-Chuyn mch CH2 AC-GND-DC ( CH.I GD AC-DC) t AC (Phm AC-

DC nh);

-Thay i v tr chuyn mch CH2 (CH.I) VOLT/DIV v iu chnh nm

VARIABLE di tia theo trc Y l 6 vch;

-Chuyn dch tia v trung tm mn hnh nh nm CH2-POSITION ( Y-

POS.I);

-Chuyn mch CH1 AC-GND-DC ( CH.II GD AC-DC) chuyn v v tr AC

(Cc phm GD , AC-DC nh) , Trn mn hnh xut hin hnh elp, v d nh dng

biu din trn hnh 2.8.

Hnh 2.8

Ch : Kt qu qu iu chnh cho tn hiu bng nhau a ti 2 cp phin Y

v X ca MHS, nn trong mi trng hp hnh elp nhn c i xng qua 2

trc phn gic ca cc gc to bi h trc to XY . Chnh v vy khong cch

gia 2 im ct ca hnh elp vi trc X bng khong cch gia 2 im ct ca

hnh elp vi trc Y.

Tnh gc lch pha: = arc sin (Ny/ 6) = arc sin (Nx/6)

y Nx = Ny , Nx- s vch gia 2 im ct ca hnh elp vi trc X, Ny- s

vch gia 2 im ct ca hnh elp vi trc Y;

Kt qu thu nhn:

-Xc nh gc lch pha cho 3 trng hp: u vo CH2 or Y in (INPUT,

INPUT CH.I) ca MHS ni ln lt vi cc u ra 1, 2, 3 ca b dch pha RC

cng mt tn s;

-So snh kt qu nhn c vi kt qu php o gc lch pha ca b dch

pha RC dng ch 2 tia mc 3 phn 2.2.3.

Ch : Sau khi kt thc php o gc lch pha, ngt b dch pha khi u ra

my pht v u vo MHS, gi nguyn cc v tr nm nt ca MHS.

b/ o tn s

-iu chnh tn s my pht 27A khong 100kHz v coi y l tn s cn o;

-Ni my pht 27A th 2 ti u vo CH2 or Y in (INPUT, INPUT CH.I) ca

MHS v coi y l tn s mu ;

-Thit lp my pht th 2 ch sin, thay i v iu chnh tn s ca n

nh chuyn mch FREQ. RANGE v nm FEQUENCY cho ti thi im nhn

c hnh Lixazy n nh, v d nh hnh 2.9;

Hnh 2.9

-c tn s Fm ( Fy ) trn my pht 27A th 2;

-Xc nh s im ct ca hnh Lixazy vi mt trong cc ng li Y

(Ny=2), s im ct ca hnh Lixazy vi mt trong cc ng li X (Nx=4), ta

tnh tn s cn o theo cng thc:

Fx = Fm. Nx/ Ny

V d sau iu chnh Fm =52 kHz, theo cng thc trn Fx=104 kHz.

Kt qu thu nhn:

-Xc nh tn s theo ch X-Y ca MHS cho 2 trng hp Fx 50 kHz, 100 kHz;

-V cc hnh Lyxazy tng ng.

Bi 3

o tham s ngun n p mt chiu dng ng h vn nng v my o s vn nng

Mc ch - yu cu:


Hiu c:

-Chc nng v cc c tnh o lng c bn ca ng h vn nng v my o

s vn nng ;

-Phng php nh gi trc tip o dng in, in p, in tr ca mch

in;

Lm c:

S dng thnh tho ng h vn nng v my o s vn nng o, kim tra

cc tham s ca mch in.


Phng tin m bo:

-ng h vn nng VOLTCRAFT 2010, MF 141, CDA-701 v my o hin s

vn nng MULTIMETER 856C;

-Panel ngun n p mt chiu.

3.1.khai thc s dng ng h v my o s vn nng

3.1.1. ng h vn nng VOLTCRAFT 2010

ng h vn nng 2010 do hng Conrad Electronic ch to l phng tin o

ch th kim vi chc nng o in p, dng in mt chiu v xoay chiu, o in

tr, kim tra tham s ca it, tranzitor...

c tnh k thut c bn ca ng h vn nng 2010;

-in tr vo theo dng mt chiu: 20 k /V;

-in tr vo theo dng xoay chiu: 8 k /V;

-o in p mt chiu vi cc thang: 0,1-2,5-10-50-250-1000V;

-o in p xoay chiu vi cc thang: 10-50-250-1000V;

-o dng in mt chiu vi cc thang: 50A- 2,5mA- 25mA-250mA-10A;

-o dng in xoay chiu vi thang: 10A;

-o in tr vi cc thang: 2 k- 20 k- 2 M- 20 M;

-Sai s o in p,dng in mt chiu v in tr: 3 %;

-Sai s o in p,dng in xoay chiu : 4 %;

-Ngun nui : Pin 9 V.

Khi s dng cn ch :

-Cn chuyn cng tc v v tr AC 10 A khi o dng xoay chiu 10A, v v tr

DC 10 A khi o dng mt chiu 10A;

-Cn u ng cc tnh khi o dng in v in p mt chiu;

-Cn t ng v tr ca chuyn mch theo chng loi i lng o;

-Khi o in p, dng in nm trong gii hn cho php ca ng h o

nhng khng r khong gi tr, cn t chuyn mch thang cao nht ri gim

dn, sao cho kim ch th nm phn cui phm vi o ca thang la chn nu iu

ny l c th;

-Trc khi o in tr cn chp que o v xoay nm chnh 0 ADZ cho ng h;

-Mch cn o dng in 10A (AC, DC ) c u vo 2 cc ca ng h:

COM-, AC-DC 10A;

-Mch cn o in p, dng in di 10A, in tr c u vo 2 cc

COM-, V--A.

3.1.2. ng h vn nng MF 141

ng h vn nng MF 141 l phng tin o ch th kim vi chc nng o in p, dng in mt chiu v xoay chiu v o in tr.

c tnh k thut c bn ca ng h vn nng MF 141:

-in tr vo : 2000 /V;

-o in p mt chiu vi cc thang: 0,5-2.5-10-50-250-500V;

-o in p xoay chiu vi cc thang:0,5-2,5-10-50-250-500V;

-o dng in mt chiu vi cc thang: 0,5-1-10-100mA;

-o in tr vi cc thang: 1-10-100-1000;

-o suy gim t thang 10V xoay chiu;

-Cp chnh xc o in p, dng mt chiu v in tr: 2,5;

-Cp chnh xc o in p,dng in xoay chiu : 5,0;


Cng ging nh VOLTCRAFT 2010 khi s dng ng h vn nng MF 141

cn lu ti cc tnh in p v dng in mt chiu, ln ca dng v p, chnh 0 trc khi o in tr...

3.1.3. ng h vn nng s CDA-701

CDA-701 l phng tin o vn nng 3,5 digit do hng Sanwa Electric ch

to. N c chc nng: o in p, dng in mt chiu v xoay chiu, o in tr,

kim tra tham s ca it...

c tnh k thut c bn ca ng h vn nng CDA-701:

-T ng chn ch o mt chiu-xoay chiu;

-T ng chuyn thang v bo qu thang;

-in tr vo : 5 M ;

-o in p mt chiu vi cc thang: 0,2-2-20-200-1000V , sai s:

(0,6%UX + 2 n v hng cui) i vi thang 0,2V,

(Tip sau ta vit tt: (0,6%UX + 2)

(1,0%UX + 2) i vi cc thang cn li;

-o in p xoay chiu vi cc thang: 2-20-200-750V, sai s:

(0,8%UX + 5) i vi thang 0,2V,

(1,2%UX + 5) i vi cc thang cn li;

-o dng in mt chiu vi cc thang: 200mA-2A-12A, sai s:

(1,5%IX + 2) i vi thang 200mA v 2A ,

(2,0%IX + 2) i vi thang 12A;

-o dng in xoay chiu vi thang: 200mA-2A-12A, sai s:

(1,5%IX + 5) i vi thang 200mA v 2A ,

(2,0%IX + 5) i vi thang 12A;

-o in tr vi cc thang: 200 - 2k - 20k - 200k -2000k -20M, sai s:

(1,0%RX + 4) i vi thang 200,

(4,0%RX + 2) i vi thang 20M,

(1,0%RX + 2) i vi cc thang cn li;

-Ch th in p, dng in theo gi tr hiu dng;


Khi s dng cn ch :

-Phi tt ngun khi kt thc php o ( Cng tc POWER gt sang phi -

OFF);

-Cn t ng v tr ca chuyn mch chng loi i lng o;

- o in p, dng in thang 200mA, in tr, o tham s it...cn dng

2 u vo: COM- v ''V,,200mA...'' ;

- o dng in 2A hoc 12A cn dng cc u vo: COM- v ''2A'' hoc

COM- v ''12A''.

3.1.4. My o s vn nng MULTIMETER 856C

MUlTIMETER 856C l phng tin o vn nng 4,5 digit do hng

LEADER ch to. N c chc nng: o in p, dng in, in tr, tn s, kim

tra tham s ca it; ngoi ra cn c chc nng so snh kt qu o, tnh ton, lu

gi s liu, kho bn phm...

1. c tnh k thut c bn ca MULTIMETER 856C:

-Thang o c th c chn theo ch t ng hoc bng tay;

-T ng bo qu ti bng hin th v m thanh;

-Ch th in p, dng in theo gi tr hiu dng;

- C th c c trc tip in p theo n v dBm;

-C th o lch tham s o u vo so vi mc chun c chn trc;

-Ngun nui : in p li 220V, 50Hz;

-Dng i lng o c bn, phm vi o, sai s, tr khng vo, phn di a ra bng 3.1, 3.2, 3.3, 3.4, 3.5; y sai s c tnh: % ca gi tr c c s n v ca hng cui cng.

Bng 3.1- in p mt chiu

Thang o Ch th phn di Sai s Tr khng vo

300 mV 299.99 mV 10 V 0,03 2 1000 Mmin

3 V 2.9999V 100 V 0,05 2 11M5%

30 V 29.999 V 1 mV 0,05 2 10M5%

300 V 299.99 V 10 mV 0,05 2 10M5%

1000 V 1000.0 V 100 mV 0,05 2 10M5%

Bng 3.2- in p xoay chiu (Gi tr hiu dng)

Sai s

Thang

o

Ch th

phn

di

40Hz-

10kHz

10kHz-

20kHz

20kHz-

100kHz

Tr

khng

vo

3 V 2.9999V 100 V 0,430 140 5100 11M5%

30 V 29.999V 1mV 430 140 5100 10M5%

300 V 299.99V 10mV 430 140 5100 10M5%

750 V 750.0 V 100mV 130 (40 Hz - 1 kHz) 10M5%

Bng 3.3 -Dng mt chiu, xoay chiu

(hiu dng, tn s 40Hz-1kHz)

Thang

o

Ch th Phn

di

Sai s dng

mt chiu

Sai s dng

xoay chiu

Tr khng

vo

300mA 299.99mA 10A 0,5 2 1,5 40 1,0

3000mA 2999.9mA 100A 0,7 2 1,7 40 0,1

Bng 3.4 - in tr

Thang o Ch th phn di Sai s in p h mch

300 299.99 0,01 0,15 3,0 V

3 k 2.9999 k 0,1 0,72 1,2 V

30 k 29.999 k 1 0,72 1,2 V

300 k 299.99 k 10 0,72 1,2 V

3 M 2.9999 M 100 0,12 1,2 V

30 M 29.999 M 1000 0,35 1,2 V

Bng 3.5 - Tn s

Thang o Ch th phn di Sai s

5 Hz - 1 kHz 999.99 Hz 0,01 Hz 0,02 2

1 kHz- 10 kHz 9.9999 kHz 0,1 Hz 0,02 2

10 kHz - 100 kHz 99.999 kHz 1 Hz 0,02 2

100 kHz - 300kHz 300.00Hz 10 Hz 0,02 2

2. Cc k hiu v nm nt iu khin trn mt my ( Xem bng 3.6)

Bng 3.6

Khi chc

nng

K hiu

nm nt

Chc nng

Ngun POWER

ON/OFF

Cng tc ngun, bt (ON)-n xung

A

Phm cng n bo, khi n n bo sng-o

dng in mt chiu, tip theo ta quy c l

phm

V Phm n xung, o in p mt chiu

~A Phm n xung, o dng in xoay chiu

~ V Phm n xung, o in p xoay chiu

Phm n xung, o in tr

Phm n xung, kim tra it

Phm n xung, kim tra lin tc

FUNGTION

-Khi chuyn

mch chc

nng chnh

(Khi phm

cng tc-n

no n xung

chc nng

c chn v

n ch th

sng)

PREQ

Phm n xung, o tn s

dB Khi chc nng ~V c chn nu phm ny n xung th chc nng dBm/dB c thit

lp

HOLD Phm n xung chc nng gi s liu c

thit lp

SELECT Phm n xung, mt trong cc chc nng ph

cho php c la chn

RELATIVE Phm n xung, chc nng o lch c

chn

Khi chuyn

mch v iu

khin cc

chc nng

ph (Khi

phm cng

tc-n no

n xung

chc nng

c chn v

n ch th

sng)

(*)

COMPARE Phm n xung, chc nng so snh c

chn

KEYLOCK Phm n xung, chc nng kho bn phm

thit lp

START/STOP Phm n xung, chc nng so snh kt thc

(*)

LOCAL Phm n xung, chc nng iu khin t xa

c thit lp

Phm n xung, ch chn thang o c thit lp t ng

Tng ng vi tng i lng, thang o tng ln mt mc sau mi ln n phm

RANGE

AUTO

Chuyn mch

iu khin

chuyn thang

Tng ng vi tng i lng,thang o gim xung mt mc sau mi ln n phm

HI/dBm,GO,

LO/dB

n bo kt qu so snh, ch n v ch

o dBm/dB

299.99V(A,, Hz...)

Hin th kt qu o

Mn hin

th

s LED vch tng ng th t thang

V/,FREQ... HI - LO

2 u ni mch o in p, in tr. tn s,

ni it...

Cc u ni

tn hiu

LO - A 2 u ni mch o dng in

3. Mt s iu cn nh khi s dng my

- phc cho ni dung th nghim-thc hnh hc vin ch khai thc cc chc

nng chnh ca my nh o dng in, in p, in tr v tn s, do hn ch

s dng cc phm thuc chc nng ph;

-in p ln nht cho php gia 2 u HI v LO: 1000VDC, 750VAC;

-Dng in ln nht cho php gia 2 u LO v A: 3A ;

-Khi o dng in v in p mc thp trnh nhiu tc ng khng c

xon 2 dy o vo nhau;

-in p, dng in cc tnh m trn mn hin th ch du ''-'', cc tnh dng

khng ch du;

-Khi o ch chn thang bng tay nu trn mn hin ch "OFF'' th chng

t gi tr i lng o vt gii hn thang, lc ny cn bm phm chuyn thang;

-Khi bm nhm phm HOLD, s liu c gi li , hu ht cc phm chc

nng b v hiu ho, lc ny cn bm vo phm HOLD mt ln na my

chuyn sang chc nng ta cn;

-Khi bm nhm phm KEYLOCK, bn phm b kho (cc phm chc nng b

v hiu ho tr phm HOLD), lc ny cn bm gi phm KEYLOCK trong thi

gian khong 2s my chuyn sang chc nng ta cn.

4. Tin hnh cc php o dng my o 856c

a/ Cc thao tc o:

-n phm cng tc ngun POWER(ON), n ngun pht sng;

-n mt trong cc phm chc nng khi chuyn mch FUNCTION chn i lng o, lc ny thang o c thit lp t ng:

-Ni tn hiu ti 2 u vo HI v LO nu nh ta o mt trong cc i lng:

in p, in tr, tn s, tham s it, kim tra lin tc;

-Ni tn hiu ti 2 u vo LO v A nu nh o dng in;

Trn mn hin s s ch gi tr cng du (nu c) v n v ca i lng o.

Khi chuyn chc nng o cn n phm chn i lng v ni tn hiu ti 2 u

tng ng.

Ch :

Khi n vo phm ch o lin tc c chn . Trong ch ny ting ''bp'' xut hin nu tr khng gia 2 im o nh hn 50, iu ny rt thun li khi kim tra thng hoc chp mch;

Khi o tn s, thang o c chn t ng , cn nhy u vo c chn bng tay nh s dng cc phm tng hoc gim nhy ca my, tu thuc vo mc tn hiu vo. Mi ln n phm hoc phm mc suy gim tng

ln hoc gim i 1/10. Trn bng 3.7 a ra s liu v ln ca tn hiu vo v

mc suy gim tng ng .

Bng 3.7

Mc suy

gim

nhy cc i ca

my

in p nh cc

i u vo

S LED vch

tng ng

1/1 225 mVrms 3 V 1

1/10 2,25 Vrms 30 V 2

1/100 22,5 Vrms 300 V 3

1/1000 225 Vrms 1000 V 4

1/10000 Khng ch nh 1000 V 5

b/ Chuyn thang bng tay:

-n phm trong khi RANGE AUTO, my chuyn t ch chn thang o t ng sang ch chn bng tay;

-n phm (tng) hoc phm (gim ) chn thang o thch hp, s LED vch trn mn hin th ch th t thang thit lp.

c/ Chc nng so snh:

Chc nng so snh c thit lp cho tt c cc ch o tr o tn s v

kim tra lin tc. Cc bc tin hnh nh sau:

Thit lp thang ca ngng so snh

-n phm trong khi RANGE AUTO;

-n phm (tng) hoc phm (gim ) chn thang so snh thch hp, s LED vch trn mn hin th ch th t thang thit lp.

Thit lp gii hn trn

-n phm COMPARE, trn mn hin th ''HI/dB'', ch s hng cao nht nhp nhy;

-Dng 2 phm thit lp ch s ta cn; -n phm dch chuyn ch s nhp nhy sang hng thp hn tip theo; -Qu trnh thit lp ch s hng c lp li mt cch tng t cho ti

hng thp nht kt thc cc bc thit lp tr s; lc ny tt c cc hng ca s

thit lp khng nhp nhy;

-n phm chn du ''+'' (du ''+'' khng hin th), hoc n phm chn du ''-'';

Thit lp gii hn di

-n phm SELECT, trn mn hin th ''LO/dB'', ch s hng cao nht nhp nhy;

-Qu trnh thit lp tr s, du ca gii hn di c thc hin tng t nh

trng hp gii hn trn.

Bt u chc nng so snh

n phm START/STOP, chc nng so snh bt u, n bo chc nng so snh ''COMPARE'' s thay i t trng thi nhp nhy sang trng thi sng lin tc. Khi gi tr i lng o nm gia 2 ngng , trn mn hin ch ''GO '' v gi tr i lng; Nu nm ngoi ngng th ch ''GO '' khng hin sng.

Kt thc chc nng so snh

-n phm START/STOP, chc nng so snh kt thc, n bo chc nng so snh tr v trng thi nhp nhy;

-Nu n tip phm START/STOP chc nng so snh c thit lp li.

Ch : Sau khi thit lp gii hn trn v di, nu n phm START/STOP cc

gi tri thit lp khng c lu gi. Nu ta thit lp nhm ngng thp LO cao hn ngng cao HI th trn mn hin th ch " E.rror''.

Hu b chc nng so snh

hu b chc nng so snh cn n mt trong cc phm sau y:

-KEYLOCK;

-Mt trong cc phm ca khi FUNGTION;

-SELECT;

-HOLD khi ang s dng chc nng ~ V.

3.2. o-kim tra tham s ngun mt chiu

3.2.1. Ngun n p mt chiu

Trn hnh 3.1 a ra s chc nng ngun n p mt chiu c in p danh

nh +5V. N c xy dng t cc khi chc nng: Bin p, cu chnh lu, n

p +5V trn vi mch 7805.

+ I~ - + I- - K1 K2 K3 K4

220V U Ucl Ut Rt Hnh 3.1

3.2.2. o tham s ngun n p mt chiu

Cc tham s cn o:

-in p, dng in xoay chiu cun th cp ca bin p;

-in p, dng in mt chiu sau chnh lu;

-in p trn ti v dng in qua ti Rt1 v Rt2;

-in tr ti Rt1 v Rt2.

Phng tin o s dng:

-ng h vn nng ch th kim VOLTCRAFT 2010, MF 141;

-ng h vn nng hin s CDA-701, my o hin s 856c.

Mt s iu cn lu trc khi o:

-Tm hiu k tnh nng k thut v cch s dng cc phng tin o nu trn;

-S dng tng phng tin o o ln lt cc tham s ca ngun;

-Khi o dng Ampemt mc ni tip vi ti; khi o in p, in tr Vn-

mmt mc song song vi ti;

-Khi o dng cc cng tc K2, K3 h, khi o p cc cng tc chp;

Bin p

Cu

chnh lu

n p 7805

-Khi o in tr ti cn ngt ngun cp cho n p;

-Khi o in tr Rt1 cng tc K3 chp v pha Rt2, ngc li khi o Rt2 cng

tc K3 chp v pha Rt1;

-Cn ch u ng cc tnh ca ng h ch th kim.

Kt qu thu nhn:

in cc s liu o theo mu bng 3.8 v tnh sai s o

Bng 3.8

TT i lng o Voltcraft

2010

MF 141 CDA-701 856c

1 in p th cp BA

Sai s (%)

2 Dng th cp BA

Sai s (%)

3 in p sau CL

Sai s (%)

4 in p trn ti Rt1

Sai s (%)

5 Dng qua ti Rt1

Sai s (%)

6 in tr ti Rt1

Sai s (%)

7 in tr ti Rt2

Sai s (%)

8 Tn s th cp BA x x x x x x x x x

Sai s (%) x x x x x x x x x

Ch :

-Sai s o dng VOLTCRAFT 2010 a ra phn 3.1.1;

-Sai s o dng MF 141 c tnh thng qua cp chnh xc:

= (C . Xd. / X ) , %

y C -cp chnh xc a ra mc 1.2, Xd. - gi tr danh nh ca thang o,

X - kt qu ch th;

-Sai s o dng CDA-701 c tnh theo cc cng thc a ra phn 3.1.3;

-Sai s o dng my o 856c c tnh theo cc cng thc a ra cc bng

3.1 n 3.5.

3.2.3. Kim tra n nh in p ra ngun n p mt chiu

Qu trnh kim tra n nh in p ra ngun n p mt chiu c thc

hin nh chc nng so snh ca my o vn nng 856c. y gii hn trn l +5,1 V, gii hn di l +4,9 V. Thi gian kim tra l 1 pht cho mi ph ti Rt1,

Rt2.

Cc bc tin hnh nh sau:

Thit lp ch kim tra in p ra ca ngun vi ph ti Rt1

Thit lp thang bng tay ca ngng so snh

-n phm trong khi RANGE AUTO;

-n phm tng hoc phm gim (nu cn) chn s LED vch l 3 trn mn hin th, tng ng vi thang DC 30V.

Thit lp gii hn trn +5,1 V

-n phm COMPARE, trn mn hin th ''HI/dB'', ch s 0 hng cao nht nhp nhy;

-n phm chn ch s 0 v dch chuyn ch s nhp nhy sang hng thp hn tip theo;

-Dng 2 phm thit lp ch s 5 ta cn; -n phm dch chuyn ch s nhp nhy sang hng thp hn tip theo; -Dng 2 phm thit lp ch s 1;

-Qu trnh thit lp cc ch s 0 cn li cc hng tip theo c lp li mt

cch tng t cho ti hng thp nht kt thc cc bc thit lp s 5,1; Lc

ny tt c cc hng ca s thit lp khng nhp nhy;

-n phm chn du ''+'' (du ''+'' khng hin th). Thit lp gii hn di +4,9 V

-n phm SELECT, trn mn hin th ''LO/dB'', ch s hng cao nht nhp nhy;

-Qu trnh thit lp tr s, du ca gii hn di c thc hin tng t nh

trng hp gii hn trn. Bt u chc nng so snh

n phm START/STOP, chc nng so snh bt u, n bo chc nng so snh ''COMPARE'' s thay i t trng thi nhp nhy sang trng thi sng lin tc. Khi gi tr i lng o nm gia 2 ngng , trn mn hin ch ''GO '' v gi tr i lng; Nu nm ngoi ngng th ch ''GO'' khng hin sng.

Kt thc chc nng so snh

-n phm START/STOP, chc nng so snh kt thc, n bo chc nng so snh ''COMPARE'' tr v trng thi nhp nhy.

Thit lp ch kim tra in p ra ca ngun vi ph ti Rt2

Ni ph ti Rt2 vi ngun. Thit lp tr li chc nng so snh vi 2 ngng

+4,8V, +5,1V nh n li phm START/STOP. Trn mn s hin th kt qu kim

tra.

Hu b chc nng so snh

hu b chc nng so snh ch cn n mt trong cc phm ca khi

FUNGTION.

Kt qu thu nhn:

-Ghi kt qu kim tra in p ca ngun vi 2 ph ti Rt1, Rt2;

-nh gi cht lng n p.

Bi 4

Nghin cu nguyn l xy dng vnmt s

tch phn hai ln v tnmt s

Mc ch - yu cu:


Hiu c:

-Chc nng ca cc khi bin i c bn ca vnmt s tch phn hai ln v

tn mt s;

-Nguyn l xy dng vnmt s tch phn hai ln v tn mt s;

Lm c:

-S dng thnh tho MHS ch hai tia hin th dng tn hiu v o cc

tham s ca tn hiu cc im kim tra trn panel vnmt s v tn mt s;

-Tin hnh thnh tho cc thao tc o th dng panel vnmt v tn mt.


Phng tin m bo:

-My hin sng: LS 1020 ( LS 1040);

-Panel vnmt s v tn mt s.

4.1.Nghin cu nguyn l xy dng vnmt s v tnmt s

4.1.1.Vnmet s thi gian-xung tch phn hai ln

Trong o lng s mt trong cc phng tin o c s dng rng ri nht

l vnmt s thi gian-xung tch phn hai ln. N c u im:

-Cu trc n gin;

-Kh nng chng nhiu cao, trong c nhiu ngun nui;

- chnh xc kh cao;

-D thay i kt cu mch in to ra cc phng tin o cc i lng

khc, trong c cc i lng khng in.

S chc nng ca vnmt tch phn a ra trn hnh 4.1. N c xy

dng t cc khi c bn sau y: b khuch vo (K), b tch phn (TP), b so

snh (SS), kho (K), cc b to in p mu (A1, A2), b to xung chun

(TXC), b m xung (X), b gii m (GM), thit b hin th s (HTS), b iu

khin (K) v khi ngun. Panel vnmt c kt cu dng vi mch ri vi cc

k hiu vit di trong mi khi l chng loi vi mch c s dng.

Qu trnh hot ng ca vnmt theo 2 bc: Trong bc tch phn th nht

t ca b tch phn TP c np in t in p vo qua b khuch i K trong

khong thi gian ng bng chu k nhiu; trong bc tch phn th hai, t in

phng ti ngun in p mu A2 cc tnh m cho n thi im in p ra b

TP bng 0 v qu trnh bin i kt thc. B m X hot ng trong thi gian

bc 2 tch phn. S lng xung thit lp trn X bin i v dng m 10, c

hin th trn HTS vi tr s ng bng in p cn o. Nguyn l hot ng ca

vnmt tch phn hai ln c th tham kho [1].

KT3

Ux CM TP C KT4

741

KT1 UKT KT2

KT6 KT5

Hnh 4.1

AM1 7805,

AM2 7805

K 741

SS 558

K 4011

GM 4511

X 4518

TXC TA 4069

HTS LED

K 4013,451

ngun

7805, 7905

4.1.2.Tnmt s

Tnmt s l mt trong nhng phng tin o quan trng trong lnh vc o

lng. N c chnh xc cao, di tn rng, d dng hiu chun...Nghin cu

nguyn tc xy dng tnmt l cn thit.

Trn hnh 4.2 a ra Panel tnmt s. Ngoi cc khi: TXC, K, X, GM,

HTS, K, khi ngun ging nh vnmt hnh 4.1, tnmt c thm chuyn

mch kp CM v cc b chia tn CT lm nhim v thay i ch o v to

khong thi gian chun. Nguyn tc bin i ca tnmt trong php o tn s l

lp y khong thi gian mu bng dy xung c tn s cn o; nguyn tc bin

i trong php o chu k l lp y chu k cn o bng dy xung c tn s cao,

n nh.

php o tn s CM bt v v tr Fx, tn s 1 MHz ca b dao ng thch anh trong TXC qua 2 b chia tn to ra khong thi gian mu, m kho K, xung

vi tn s cn o qua kho K ti b m. Kt thc qu trnh bin i trn HTS

hin th tn s cn o.

php o chu k CM bt v v tr Tx, tn s 1 MHz ca b dao ng thch anh qua kho K trong khong thi gian ng bng chu k ca tn hiu vo. S

xung X m c t l thun vi chu k cn o v HTS hin tr s ca n.

KT1 Fx KT3

CM xo

KT4 Tx

cht

KT5

KT6

Hnh 4.2

KT2

TXC TA, 4069

K 4011

X 4518

GM 4511

KHT 4011 HTS

LED

CT 4018

CT 4013

Ngun 7805

Ngun dao ng

4.2. Kho st panel vnmt tch phn s v tnmt s 4.2.1. Thit lp ch hai tia cho MHS LS1020

1. thit lp v tr cc nm nt ca MHS

a/ Khi hin th:

-Chuyn mch ILLUM t v tr mong mun;

-Nm iu chnh FOCUS xoay v tr trung gian;

-Nm iu chnh INTEN (INTENS) xoay v tr trung gian.

b/ Khi lch ng:

-Chuyn mch V-MOD t v tr CHOP;

-Hai chuyn mch VOLTS/DIV t v tr 2V;

-Hai nm VARIABLE n xung v xoay v v tr CAL;

-Hai nm CH1, CH2 POSITION xoay v v tr trung gian;

-Hai chuyn mch AC- GND-DC t GND;

c/ khi to qut:

-Chuyn mch TEME/DIV v tr 1 ms;

-Nm TEME VARIABLE xoay v v tr CAL;

-Nm H POSITION n xung v xoay v v tr trung gian;

d/ Khi ng b;

-Nm SLOPE xoay v "+" ;

-Nm LEVEL xoay v v tr trung gian;

-Nm PULL NORM/ AUTO v tr n (NORM);

-Chuyn mch SOURCE t v tr CH1;

-Chuyn mch COUPLING t v tr DC;

-Chuyn mch SOURCE t v tr CH1.

2. Cp ngun v hiu chnh

Sau khi bt cng tc ngun POWER ON/OFF v iu chnh sng nh

nm INTEN, hi t nh nm FOCUS ta thc hin tip cc thao tc sau y:

-a 2 tia v trung tm mn hnh trng vi trc X trung tm nh cc nm

CH1, CH2 POSITION v H-POSITION;

-Hai chuyn mch AC-GND-DC a v v tr DC.

4.2.2.Kho st Panel vnmt tch phn

1.Hiu chnh vnmt tch phn

-Ni tt cc u ni 1-2 trn panel vnmt;

-Bt ngun sy Panel trong 5 pht;

-Hiu chun panel in p mu 2000 mV: n gi phm K, xoay chit p UKT

thit lp trn b hin th s ca Panel vnmt tr s gn bng 2000mV( Tr s

trn b hin th nm trong khong 1990 mV n 2010 mV);

-Nh phm K, gi c nh v tr chit p UKT;

-Xoay nm chit p Ux2 nhn c trn HTS tr s in p trong khong

t 1500mV n 1800mV.

2.Kho st Panel cc im kim tra

a/ Kim tra cc tnh ca 2 in p u vo b tch ph

( MHS ch 2 tia)

-Ni cp o ti 2 u vo MHS CH1 or X in, CH2 or Y in;

-Cm u cp ca knh 1 ti im KT3 ca Panel, cm u cp ca knh 2

ti im KT2, kt qu nhn c trn mn hnh l 2 ng thng nm 2 pha

ca trc X.

Kt qu thu nhn: Kt lun v cc tnh ca 2 in p 2 u vo ca chuyn mch CM ( B tch phn), tnh gi tr ca in ra ca AM2.

b/ Kim tra tn s ra 1 MHz ca TXC

( MHS ch mtl tia)

-Hai chuyn mch AC- GND-DC t AC;

-Chuyn mch COUPLING t v tr AC;

-Cm chuyn u cp ca knh 1 ti im KT6;

-Bt chuyn mch V-MOD v v tr CH1 (Cho hin tia Y1);

-Thay i v tr ca chuyn mch VOLTS/DIV (v d nh vch 1V) v iu

chnh nm CH1 VARIABLE bin xung thch hp;

-Thay i v tr ca chuyn mch TEME/DIV nhn c dng xung c

chu k thch hp ( Nu ta t v tr 0.5 s th 1 chu k xung l 2 vch v tn s xung l 1 MHz);

Kt qu thu nhn: Tnh tn s ca TXC im KT6.

c/ V biu in p u ra b TP v kho K

( MHS ch 2 tia)

-Bt chuyn mch V-MOD v v tr CHOP (Cho hin 2 tia);



-Hai chuyn mch AC- GND-DC t GND;

-Nm CH2 POSITION xoay v v tr tia th 2 nm pha di cch trc

X 2 vch;

-a 2 chuyn mch AC- GND-DC v v tr AC;

-Thay i v tr ca 2 chuyn mch VOLTS/DIV( v d nh vch 1V) v iu

chnh 2 nm CH1, CH2 VARIABLE nh c cao thch hp;

-Thay i v tr ca chuyn mch TEME/DIV( v du nh vch 1ms) v iu

chnh nm TEME VARIABLE nhn c nh ging nh hnh 4.3

Hnh 4.3

-Xoay t t nm Ux2 theo chiu kim ng h, ng thi quan st s thay i tr s trn HTS ca Panel vnmt v s thay i dng nh trn mn hin sng.

rng ca khong thi gian bc 2 tch phn (Thi gian m xung) trong Panel

vnmt phi thay i tng ng vi ln ca gi tr in p u vo Ux2.

Kt qu thu nhn:

-V dng nh ca tn hiu 2 im KT4 v KT5 tng ng vi 2 mc in

p vo Ux2 1800 mV, 2600 mV;

-Nu nhn xt v kt qu thu nhn c.

Kt thc qu trnh kho st Panel vnmt rt cc u dy cm ra khi cc

im kim tra KT v gi nguyn v tr cc nm nt ca MHS.

4.2.2.Kho st Panel tnmt s

1.Kim tra chc nng tnmt s

-Ni tt u ni 0-1 trn panel tnmt;

-Bt cng tc Fx-Tx v v tr Fx;

-iu chnh chit p Fx,Tx trn HTS ch tr s khong 3000 Hz;

-Bt cng tc Fx-Tx v v tr Tx, trn HTS phi ch tr s khong 333 s.

2.Kho st tnmt s cc im kim tra

a/ Kim tra in p ngun ( MHS ch o 1 tia )


-Bt chuyn mch V-MOD v v tr CH1 (Cho hin 1 tia Y1);

-Chuyn mch CH1 VOLTS/DIV t v tr 2V;

-Nm CH1 VARIABLE n xung v xoay v v tr CAL;

-Chuyn mch CH1 AC- GND-DC t DC;

-Chuyn mch COUPLING t v tr DC;

-Cm u cp ca knh 1 ti im KT6, trn mn hin sng hin ng

thng nm pha trn trc X, song song v cch n 2,5 vch. in p ngun mt

chiu c xc nh:

U = 2 (V/vch) x 2,5 vch = 5 V

-Chuyn mch CH1 AC- GND-DC a v v tr AC;

-Chuyn mch COUPLING a v v tr AC;

-Chuyn mch TEME/DIV t vch 10ms;

-Xoay chuyn mch CH1 VOLTS/DIV theo chiu kim ng h ti thi im

quan st r v o c nhp nh ca ngun 5V (Ch : nu ngun c cht

lng cao ta khng quan st r nhp nh vch 0.2mV).

Kt qu thu nhn:

-V dng nh nhp nh ca ngun 5V( Nu quan st r);

-Xc nh tr s thc t ca ngun 5V v nhp nh ca n (Tnh bng mV)

trong php o;

-Nhn xt v cht lng ca ngun 5V.

b/ Kim tra tn s ca TXC v CT 1kHz ( MHS ch o 1 tia )

-Chuyn mch CH1 VOLTS/DIV t v tr 1V;

-Chuyn mch TEME/DIV t v tr 0.5 s;

-Nm TEME VARIABLE xoay v v tr CAL;

-Cm u cp ca knh 1 ti im KT5, trn mn hin sng hin nh dng

xung c chu k bng 2 vch. Tn s ca TXC c xc nh:

F1 = 0,5 (s/vch) x 2 vch = 1 MHz.


-Chuyn mch TEME/DIV a v v tr 0.5 ms, trn mn hin sng hin nh

dng xung c chu k bng 2 vch. Tn s ca TXC c xc nh:

F2 = 0,5 (ms/vch) x 2 vch = 1 kHz.

Kt qu thu nhn:

-Xc nh tn s thc t ca TXC, CT 2 im KT5, KT6 trong php o;

-Nhn xt v dng xung ca 2 tn hiu trn.

c/ Kim tra tn s ca tn hiu vo ( MHS ch o 1 tia )



-Thay i v tr ca chuyn mch TEME/DIV( V d nh ti vch 0.2ms) v

iu chnh nm TEME VARIABLE cho n khi nhn c dng xung r nt;

-Tng t t tn s Fx nh chit p Fx, Tx, quan st ng thi trn mn hin

sng v HTS, nhn thy xt dn ca nh tng tng ng vi tr s trn HTS .

d/ Xc nh tn s ca xung ca ( MHS ch o 1 tia )


-Cm u cp ca knh 1 ti im KT2;

-Chuyn mch TEME/DIV xoay v v tr 0.2s, trn mn hin sng l nh ca

dy xung ca hin theo chu k 2s mt ln. Nh vy khong thi gian m kho K

v m xung ch o tn s l 1s trong mt chu k xung ca.

e/ Quan st dng tn hiu cc u KT1, KT3 ch o chu k

( MHS ch 2 tia )


-Bt cng tc Fx-Tx v v tr Tx, trn HTS ch gi tr khong 330s;



-Bt chuyn mch V-MOD v v tr CHOP (Cho hin 2 tia );

-Hai chuyn mch CH1, CH2 VOLTS/DIV t v tr 1V;

-Chuyn mch TEME/DIV v nm TEME VARIABLE xoay v v tr thch

hp trn mn hin sng l nh ca dy xung c chu k cn o v dng xung

sau kho K (Xem hnh 4.4). Nh vy xung t TXC tn s 1MHz qua kho K lp

y khong thi gian ng bng chu k tn hiu Tx.

Kt qu thu nhn:

V dng tn hiu u KT1, KT3 ch o chu k.

Hnh 4.4

4.3. O TH dng panel vnmt s v tnmt s 4.3.1. o in p bng Panel vnmt dng vi mch 7107

Vi mch t hp 7107 l b bin i tng t-s c s dng kh rng ri.

N c kt cu n gin, gi thnh r , d lp rp v s dng. Vi mch 7107 lp

rp cng b khuch i vo, cc b gii m, LED 7 thanh v khi ngun to

thnh vnmt s vi mc in p cc i o c l 1999mV.

Tin hnh o th: Thay i in p vo nh chit p Ux1 ta nhn c trn

HTS tr s t 0 mV n 1800mV.

4.3.2.o in p dng Panel vnmt tch phn

Hiu chun Panel vnmt in p mu 2000 mV

-n gi phm K, xoay chit p UKT thit lp trn HTS tr s gn bng 2000mV( khong 1990 mV n 2010 mV);

-Nh phm K, gi c nh v tr chit p UKT.

Tin hnh o th: Thay i in p vo nh chit p Ux2 ta nhn c trn

HTS tr s t 1000 mV n 3000mV .

4.3.3.o tn s, chu k dng Panel tnmt

Tin hnh o th:


-Thay i tn s nh chit p Fx,Tx ta nhn c trn HTS tr s t 2700Hz

n 4500Hz;

-Bt cng tc Fx-Tx v v tr Tx;

-Thay i tn s nh chit p Fx,Tx ta nhn c trn HTS tr s t 222s n 370s;

-Bt cng tc Fx-Tx v v tr Fx, o 2 tn s Fx 3000Hz, 4000Hz, bt cng tc Fx-Tx v v tr Tx, tin hnh o chu k tng ng ;

-Tnh tn s thng qua php o chu k so snh kt qu.

Kt qu thu nhn:

-So snh kt qu o tn s trc tip v gin tip thng qua php o chu k

dng Panel tnmt s;

-Nhn xt v cc kt qu o th dng Panel vnmt s v tnmt s.

Bi 5

o tn s, chu k tn hiu ca my pht

o lng dng tnmt s

Mc ch - yu cu:


Hiu c:

-Chc nng, cc c tnh o lng c bn v cc nm iu khin v iu

chnh ca ca my pht tn hiu chun 3214 v tnmt s LDC-823A;

-Chc nng thit lp tn s, mc tn hiu, tn iu bin v iu tn ca my

pht 3214 ;

-Cc thao tc o tn s, chu k tn hiu dng tnmt s LDC-823A;

Lm c:

-S dng thnh tho my pht 3214 theo chc nng thit lp tn s v mc

tn hiu;

-S dng thnh tho tnmt s LDC-823A.


Phng tin m bo:

-My pht hin s 3214 ;

-Tnmt s LDC-823A.

5.1.khai thc s dng My pht hin s 3214

v tnmt s LDC-823A

5.1.1. My pht hin s 3214

1.Cc tnh nng k thut c bn

My pht Model 3214 l my to tn hiu chun ng b, thay i lin tc

v cc tn hiu iu bin v iu tn t 100kHz n 150MHz. Model 3214 c b

iu ch FM Stereo.

My pht hin s 3214 c cc ch tiu k thut sau y:

Tn s

-Di tn 100kHz - 150MHZ

- phn di 1 kHz

-Thit lp tn s bng cc phm chn ch s v b m ho quay s

- chnh xc ( 5x10-5 + 50Hz )

-Hin th 6 ch s

Tn hiu ra

-Mc 0 - 99dBm ( 0 dBm = 1 V

- phn di 1dB

-Thit lp mc bng cc phm chn ch s v b m ho quay s

- chnh xc thit lp 2dBm

-Tr khng 50, t hn 1,3

-Hi 30dB (tn s 200kHz) hoc thp hn (tn s ln hn 200kHz)

-Hin th 2 ch s

iu ch

*iu tn FM:

- lch tn 22,5kHz, 75kHz -t trc

0-100kHz -Thay i lin tc

(Tn s sng mang khng di 1,1MHz )

- chnh xc iu ch 10kHz - lch 75kHz

3kHz - lch 22,5kHz

-H s mo 0,1% max- tn s sng mang 74-110MHz

lch 75kHz, AF 1kHz

-H s tn/tp khng di 70dB - tn s sng mang

74 - 110MHz lch 75kHz

*iu bin AM:

-H s iu bin 30% -t trc

0-50% -Thay i lin tc

- chnh xc iu ch 5% gi tr thit lp

-H s mo 0,5% max- tn s sng mang 200kHz -2MHz,

30% iu ch, AF 1kHz

3% max- 30% iu ch, AF 1kHz

-H s tn/tp khng di 50dB - tn s sng mang

200kHz - 2MHz, 30% iu ch, AF 1kHz

iu ch trong 400Hz, 1kHz 5%

iu ch ngoi

- Tr khng vo 10 k

- Mc vo 1,0Vrms

-Di tn FM: 20Hz- 100kHz

AM: 20Hz- 10kHz

iu ch FM Stereo

Cc tham s khc

-Nhit mi trng lm vic 10-35OC

- m khng vt 85%

-Ngun nui 100, 120, 220, 240VAC 10%(250 VACmax)

2.Cc nm iu khin v iu chnh trn mt my ( Xem bng 5.1)

Bng 5.1

Khi

chc

nng

K hiu Chc nng, nhim v

POWER ON/OFF Cng tc ngun

FREQUENCY... Ch th tn s t 0,1MHz-150MHz

Hin th

OUTPUT LEVEL Ch th mc ra 0 dB -99 dB

OUTPUT (50) u ra vi tr khng 50

LEVEL Phm mc cng n hiu (gi tt l phm,

khi n , n sng) khi n sng mc ra c

th iu chnh bng nm DOWN-UP

DOWN-UP Nm iu chnh tng-gim mc ra (tn s

ra)

FREQ Phm tn s, khi n sng tn s ra c th

iu chnh bng nm DOWN-UP ( Hai

phm LEVEL v FREQ hot ng theo

ch lun phin)

FREQ-

LEVEL

Khi

phm

thit lp

tn s

v

mc ra DIGIT Gm 2 phm dng dch chuyn ln lt

cc hng trn hin th tn s v mc ra

MOD ON Phm bt chc nng iu ch

AM Phm iu bin

FM Phm iu tn( Hot ng lun phin cng

phm AM)

MODU-

LATION

Khi

phm AM 30%-

FM 22.5kHz

Phm iu bin 30% hoc lch tn ti

22,5kHz

FM 75 kHz Phm iu tn 75kHz (khi ch AM

phm ny khng c tc dng)

iu ch

(*)

400Hz/1kHz Phm chuyn mch tn s iu ch trong

400Hz v 1kHz (n-400Hz, nh -1kHz)

EXT Phm iu ch ngoi

INT Phm thit lp iu ch trong

MOD MONITOR u ni vi mili-vnmt kim tra h s

iu ch:

-FM-trong: 10kHz/100mVrms

-AM-trong: 5%/100mVrms

(*)

MOD LEVEL Nm iu chnh h s iu ch trong(AM:

0-50%, FM: 0-100kHz)

PILOT ON Phm bt tn hiu PILOT ch FM,

lch PILOT c nh 7,5kHz

STEREO Phm chuyn mch stereo(n sng)-mono

iu ch

STEREO L, R, MAIN, SUB Cc phm chuyn cc ch stereo, nu

phm no n th n sng,ch c thit

lp;

y MAIN: L=R(cng pha),

SUB: L=-R(ngc pha)

EXT MOD

INPUT-L(MONO)

u vo tn hiu iu ch

- Knh L (mono)

R u vo knh R

Mt sau

my

REMOTE Gic ni iu khin t xa

Trn hnh 5.1 a ra cu hnh ngun iu ch trong my pht 3214.

Thay i Phm INT

Hnh 5.1 Trong

C nh Phm AM 30%

Ngun iu ch Phm FM 75kHz

Ngoi Phm EXT

3.Thit lp cc ch ch c bn cho my pht

a/ Thit lp tn s

thit lp tn s, thc hin cc thao tc sau:

-n phm FREQ;

-n mt trong hai phm DIGIT dch chuyn ch s sang tri hoc sang phi ti hng c ch s cn thit lp;

-Xoay nm DOWN-UP thit lp ch s mong mun;

-Qu trnh nu trn c lp li thit lp cc ch s cc hng cn li.

b/ Thit lp mc u ra

thit lp mc u ra, thc hin cc thao tc sau:

-n phm LEVEL;

-n mt trong hai phm DIGIT dch chuyn ch s sang tri hoc sang phi ti hng c ch s cn thit lp;

-Xoay nm DOWN-UP thit lp ch s mong mun;

-Qu trnh nu trn c lp li thit lp ch s hng cn li.

c/ Thit lp iu bin trong

thit lp ch iu bin trong , thc hin cc thao tc sau:

-n phm MOD ON;

-n phm AM;

-Dng phm 400Hz/1kHz chn tn s iu ch;

-Chn n phm AM 30%-FM 22.5kHz nu cn h s iu bin 30%;

-Chn n phm INT ri xoay nm MOD LEVEL nu cn h s iu bin thay

i t 0 n 50%.

d/ Thit lp iu bin ngoi

thit lp ch iu bin ngoi, thc hin cc thao tc sau:

-n phm MOD ON;

-n phm AM;

-Dng phm EXT chn tn hiu iu ch ngoi;

-a tn hiu iu ch (1mVrms) ti u vo EXT MOD INPUT (mt sau

my)

-Ni u ra MOD MONITOR vi mili-vnmt (h s 5%/100mV-in p h

mch) theo di h s iu bin;

-Xoay nm MOD LEVEL thit lp h s iu bin mong mun.

e/ Thit lp iu tn trong

thit lp ch iu tn trong , thc hin cc thao tc sau:

-n phm MOD ON, n phm FM;

-Dng phm 400Hz/1kHz chn tn s iu ch ( n-400Hz, nh-1kHz);

-Xoay nm MOD LEVEL thit lp h s iu bin.

-Chn n phm AM 30%-FM 22.5kHz nu cn lnh tn 22,5kHz

-Hoc chn n phm FM 75kHz nu cn lnh tn 75kHz

-Hoc chn n phm INT ri xoay nm MOD LEVEL nu cn lch tn

thay i t 0 n 100kHz

f/ Thit lp iu tn ngoi

- thit lp ch iu tn ngoi, thc hin cc thao tc sau:

-n phm MOD ON, n phm FM;

-Dng phm EXT chn tn hiu iu ch ngoi;

-a tn hiu iu ch ti u vo EXT MOD INPUT ( mt sau my)

-Ni u ra MOD MONITOR vi mili-vnmt (h s 10kHz/100mVrms-

in p h mch) theo di lch tn ;

-Xoay nm MOD LEVEL thit lp lch tn mong mun.

5.1.2.Tnmt s LDC-823A

1.Cc tnh nng k thut c bn

Tnmt s LDC-823A l phng tin o tn s v chu k ca tn hiu phm

vi o 10Hz - 250MHz vi mc vo cc i 20mVrms, vi 8 ch s hin th.

Tnmt s LDC-823A c cc ch tiu k thut sau y:

o tn s

- Phm vi o 10Hz - 250MHz gm 2 thang: 10Hz-80MHz, 10Hz-250MHz

-Thi gian m 0,1s, 1s, 10s

- phn di 10Hz, 1Hz, 0,1Hz (thang thp)

100Hz, 10Hz, 1Hz (thang cao)

-Sai s 1v hng thp nht sai s b dao ng chun

o chu k

-Phm vi o 100ms-1s

-H s nhn chu k x10, x100, x1000 (dch du phy hin th)

- phn di 10s, 1s, 0.1s 100Hz, 10Hz, 1Hz (thang cao)

-Sai s 1v hng thp nht sai s b dao ng chun sai s ng b

u vo

-Mc vo 50mVrms (10Hz - 100Hz, 1M )

20mVrms (100Hz -100MHz, 1M )

50mVrms (100MHz - 250Hz, 1M )

20mVrms (100kHz -100MHz, 50 )

50mVrms (100MHz -250MHz, 50 )

-Mc suy gim 1, 1/10

-Dng tn hiu AC

-Tr khng vo 1M v 50 (h mch)

-in p vo cc i 100Vrms (10Hz-400Hz , 1M)

20Vrms (10Hz-400Hz , 1M)

5Vrms (400Hz-100kHz , 1M)

5Vrms (100kHz-250MHz , 50)

Dao ng chun

-Tn s 10MHz

-Sai s 5x10-6 (5ppm)- ( 0OC-40OC )

Cc c tnh khc

-Hin th 8 ch s dng 7 thanh

-Nhit lm vic 0OC-40OC

-in p ngun 100V, 120V, 200V, 240V 10%

(Max 250V); tn s 50-60Hz

2.Cc nm iu khin v iu chnh trn mt my (Xem bng 5.2 )

Bng 5.2

K hiu Chc nng, nhim v

(1) (2)

POWER ON Phm cng tc ngun (ON-bt)

GATE TEME:

0.1s- 1s- 10s

Chuyn mch thi gian m tn s

MULTI.

x10,x100,x1000

Chuyn mch dch du phy trong php o chu k

RESET n phm -dng m, nh phm -ch th v ''0'', sau

0,1s m tr li

PERIOD/FREQ. Chuyn mch tn s/chu k, nh-tn s, n- chu k

FREQ. RANGE

80MHz/250MHz

Chuyn mch thang tn s, nh-80MHz,

n-250MHz

SENSITIVITI

20mVrms/200mVrms

Chuyn mch mc suy gim, nh-20mVrms,

n-200mVrms

IMPEDANCE

1M/50

Chuyn mch tr khng vo, nh-1M,

n-50

(1) (2)

INPUT u vo

Mn hin th:

250.00000 MHz

10.000 ms

GATE OVER

- Gi tr tn s

- Gi tr chu k

- Bo hiu ang m

- Bo hiu qu thang

Mt sau:

-OUTPUT-INPUT

-INT/EXT

- u ra-vo ngun tn s chun

- Chuyn mch ni ngun tn s chun trong (INT)

hay ngoi (EXT)

3.Cc bc chun b o

-Ngt cp o khi u INPUT ca 823A

-Cm phch ngun, bt cng tc POWER v sy my trong thi gian khong

20 pht b dao ng thch anh lm vic n nh

-Nh phm PERIOD/FREQ.(Thit lp ch o tn s)

-Nh phm SENSITIVITI (Thit lp mc tn hiu 20mVrms)

-n phm 0.1s ca chuyn mch GATE TEME, khi phm FREQ. RANGE v tr nh (80MHz) hoc n (250MHz) th trn mn hin 0.00 kHz hoc 0.0000

MHz, cn n GATE sng trong 0,1s, ri tt trong 0,1s lun phin nhau

-n phm 1s ca chuyn mch GATE TEME, khi phm FREQ. RANGE v tr nh (80MHz) hoc n (250MHz) th trn mn hin 0.000 kHz hoc 0.00000

MHz, cn n GATE sng trong thi gian 1s, ri tt trong 1s lun phin nhau -n phm 10s ca chuyn mch GATE TEME, khi phm FREQ. RANGE

v tr nh (80MHz) hoc n (250MHz) th trn mn hin 0.0000 kHz hoc

0.000000 MHz, cn n GATE sng trong thi gian 10s, ri tt trong 10s lun phin nhau

-n phm PERIOD/FREQ.(Thit lp ch o chu k)

-n ln lt cc phm .x10, x100, x1000 ca chuyn mch MULTI. ta nhn c trn mn ch th cc gi tr a ra trn bng 5.3.

Bng 5.3

Chuyn mch MULTI Ch th

x10 0.00 ms

x100 0.000 ms

x1000 0.0000ms

-Sau 6-10 ln hin th, n bo OVER s tt.

Ch :

-Khi tn hiu vo c tr s ln ta cn dng b ni ghp BNC (i km vi

my). Tn hiu qua b ni ghp, thnh phn mt chiu b chn li;

-Mc cho php v di tn ca tn hiu vo tu thuc vo vic chn tr khng

vo thng qua chuyn mch IMPEDANCE (Xem ch tiu k thut);

-Nu tn hiu vo thay i trong di 0,02-0,2 Vrms th t mc tn hiu vo

0.02Vrms nh phm SENSITIVITI; nu tn hiu vo thay i trong di 0,2-2Vrms

- t mc 0.2Vrms;

-Kh nng chng nhiu ca tnmt ph thuc v tr khng ti, thng thng

tn s thp tr khng ti 50/75, cn tn s cao -600;

- o tn s sng mang ca tn hiu iu bin cn t mc tn hiu vo VH

nm trong gii hn bin cc tiu ca ca sng mang (Xem hnh 5.2);

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