Electrical Measurements 05 Oscilloscopes
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7/22/2019 Electrical Measurements 05 Oscilloscopes
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63
8
5.1
-
, ,
.
,
. , .
.
, -
, -
() GHz.
u(t),
u1(t) u2(t), u1(u2).
.
:
. .
. -
, 30Hz ,
.
.
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64
-
. (cathode ray tube,
CRT). ,
, .
. ,
. , RAM.
, . ,
,
(liquid crystal display, LCD).
5.2
. ,
.
, -
. .
.
.
(). . -
s
.
:
, .
, .
, . ,
, .
,
:
.
.
.
,
. -
, .
,
. 5.1. -
, ,
. , -
.
, ,
.
7/22/2019 Electrical Measurements 05 Oscilloscopes
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. 5. 65
y 1
2
x
x
y
x: o()
y: ()
. 5.1
, ,
, -
. ,
, .-
,
. ,
. ,
, . . 5.1
.
.
-
.
.
, . , ,
.
. ,
, .
.
,
,
.
.
, xy.
. 5.2. lt-
Vt. ,
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66
,
. -
,
2
t t
a
V l L
H V d= (5.1)
, L, d
Va . ,
tan2
t t
a
V lH
L V d = = (5.2)
. (5.2) -
ltd, VtVa
. ,
,
. ,
. 5.2,
.
-
3035. ,
. , -
, .
L
lt
H
d
+
_
Vt
E
()
()
. 5.2 (), ()
7/22/2019 Electrical Measurements 05 Oscilloscopes
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. 5. 67
. ,
-
, . ,
, , -
.
5.3
,
. (divisions),
,
(graticule), . 5.3.
-
. (x) 10 ,
(y), 8 .
1cm.
5.3.1
. -
.
. 5.4, -
. . 5.4
. 4 (1:1, 10:1, 100:1 1000:1),
(1:1, 2:1 4:1). 12 ,
Volts/div.
-x
-y
. 5.3
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68
usw
Time/div.
Flip-Flop
+ _
TimeCAL.
+
_
SLOPE+/-
Line
Triggerselector
AC
DC
HF
LF
External
Trigger
usf
f
ucomp
1:110:1
100:1
1000:1
1:12:14:1
Y-1
INVERTY-Position
Volts/div.
VoltsC
AL.
Y-1
Y-1
Y
Y
X
1:110:1
100:1
1000:1
1:12:14:1
Y-2
Y-Position
Volts/div.
Y-2
Y-2
Chopper
uc
h
ALT./CHOP
Volt
sCAL.
INT./EXT.
TRIG.CH.1-2
Trigg
er
driver1
Trigger
driver2
6
.3Vac
-1900V
-1878V
1234
G
-V
+V
+V
-V
X
Intensity
Focus
TR
C C
1
2
./NORM.
Q
Reset
Set
X-Position
X-Y
DC,AC,GND
LEVEL
DC
C G
ND
GND
C
DC
Delay
Line
DelayON-OFF
. 5.4
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. 5. 69
RC,
. ,
.
, ,
1 10pF.
, .
.
, (1cm). ,
.
Volts/div. , 5mv/div. (-
1:1) 20V/div. (4000:1). ,
15V/div.,
15V30005mV
YG = = (5.3)
. 5.4 . -
, ,
. Volts CAL.,
. -
,
Y. Volts CAL.
, 5
, . -
position, . , .
,
(dc ), C
(ac ). C, 100nF/500V, -
. ac -
, ,
. ac
, C-
(1/C). , ac ,
duty cycle. ,
duty cycley. (GND),
, o ,
.
, position.
-
.
. 20z
100 z . -
. -
20z 10z,
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70
10z, -
. ,
10z -
. 30MHz,
.
. 95% ,
20MHz, 2MHz. ,
20z , 3dB,
0.707.
, . -
10% 90% (. 5.5). ,
10% 90%
, 0.8cm 7.2cm.
0.35[s]
[Hz]osct
BW (5.4)
,
. , . 5.5,
Volts CAL. ,
2.5cm . , 10% 90%
2cm .
10%
5cm
100%
trm
90%
0
. 5.5
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. 5. 71
trm
tr, tosc, -
2 2
rm r osc
t t t= + (5.5)
tosc 20z, . (5.4), 17.5ns.
, trm30ns,
tr = 24.4ns (30 24.4) / 24.4 23%e= = . tosc 5rm osct t> .
5.3.2
f,
.
.
. , x,
.
Vsw1
Vsw2
Tsw
= 1ms
0.1ms/div.
5V/div.
f = 2kHz
usw
hold off
. 5.6
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usw (. 5.6), -
( ),
.
(Vsw1) Vsw2. -
,
Vsw1 Vsw2 . Vsw2
Vsw1,
. .
(hold off period)
Vsw1. hold off ,
.
Tsw= 1ms,
10 1ms
0.1ms/div.
ime/div., RC (.
5.4). Tsw,
Time CAL.
0.1ms/div.
5 (. 5.6),
1/(5 0.1ms) = 2kHzf = . 3 . -, 5V/div,
15V.
5.3.3
, f
. -
. ,
,
.
, . 5.4,
flipflop, .
. 5.7. , . 5.7,
.
, (internal triggering), (external triggering). INT./EXT.
,
. (Line) -
.
-
, ucomp low high
flipflopusff high.
flipflophigh, .
uswVsw1,
, Vsw2,
.
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. 5. 73
+
_
usff
usw
Vsw1
ucomp
Vsw2
Tsw
F.F.
Set
Q
Reset
ucomp
usff
usw
rprp
fp fp
Vsw1
. 5.7
Tsw-
(Time/div.). ,
Vsw1. flipflop,
low. flipfloplow -
Vsw1,
, .
.
flipflop
. (unblanking), ,
.
(. 5.4).
-
, (automatic triggering),
./NORM. ,
,
, .
(GND).
-
LEVEL, (normal triggering).
, . ,
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74
,
.
,
. 5.7, (rising edge), rp.
, -
(falling edge), fp. SLOPE +/-
.
-
, Trigger selector .
. AC
. DC
. F ,
,
LF .
Line, -
, .
Line -
. , Line
thyristors,
.
Trigger selector
-
. TV trigger, . 5.4,
video.
, ,
(delay line) , . -
,
. ,
.
,
(SLOPE +/-), ,
.
5.3.4
, .
. 5.4 . ,
, . ,
.
. (alternate
mode), (. 5.8).
1kHz,
(flickering). ,
flipflop .
usff .
(chopped mode), -, (. 5.8).
(chopper oscillator), MHz.
7/22/2019 Electrical Measurements 05 Oscilloscopes
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. 5. 75
H uch,
.
. ,
. -
, -
, . 5.8. ALT./CHOP.
,
flipflopchopper.
usw
1 2
()
()
usw
1
2
uch
. 5.8 () ()
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(INVERT), . 5.4 -
1, 1 (
180).
, -
.
()
+
_
F.F.
Set Q
Reset
Time/div.
Time/div.
usw_m
usw_d
Delay
Tsw_d
Tsw_m
td
()
Tsw_d
Tsw_m
usw_m
usw_d
td
. 5.9
().().
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. 5. 77
,
,
.
, usw_d (. 5.9).
Tsw_d,
Tsw_m usw_m. td, , .
(.
5.9).
, . ,
x, .
, X
Y. ,
1 2, u1(u2).
X-Y
,
Lissajous. XY
X,
. 20z,
X2MHz (3dB),
X-Y, 100kHz.
5.3.5
. 5.4 ,
(), (G) (A1, A2, A3, A4).
6.3Vac, 1900V . HAMEG 2035.
1900V 1878V,
(). usff.
Intensity ,
.
1930V.
2, (focus)
. 2 1575V.
1 3 , 4 -
+72V. 1 3,
87V, . .
-
. ,
,
.
, -
.
. ,
TR,
(trace rotation).. 5.4
20MHz, 2kV. , -
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, -
. ,
, -
15kV 20kV, 100MHz.
5.4
-
(probes). -
.
,
1M 10pF. -
,
BNC(. 5.10). -
(passive probes) :
1:1 (1X). 10:1 (10X).
100:1 (100X) 1000:1 (1000X).
,
1:1 10:1 (1X/10X). .
1:1
20V/div. 160Vpp. H
1, 100pF/m,
, .
, (10k),
100kHz.
1X, -
1//100pF, 10X.
10:1 ,
RpCp, . 5.11.
(1)
(2)
(3)
(4)
(5)
(6)
(7)
. 5.10 1:1 10:1. BNC
(1), (2), (3),
(4), (5), (6)(7),
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. 5. 79
u
uosc
()R
p
Cp
u uoscCcbl CoscRcbl Rosc
()
Rp
Cp
. 5.11 (probe) 10:1 ().
()
Rp 9, -
1 ,
10:1. H Cp
, . . 5.11-
10, , Rosc,
CoscRcbl, Ccbl
. u
, uosc
1
1 1
oscp
p p
R
j RCu u
RR
j RC j R C
+=
++ +
(5.6)
, //cbl oscR R R= cbl oscC C C= + . . (5.6) -. ,
p pR C RC= (5.7)
. (5.6)
osc
p
Ru u
R R=
+ (5.8)
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() () ()
. 5.12 10:1, .
()(), Cp()
. (5.7) Cp
10:1,
.
, . 5.12. . 5.12, Cp.
10X, -
, .
10//16pF. , -
,
.
10(5Hz).
. -
, 50Hz,
10M, 50MHz 1.5k.
,
1X. -
(Volts/div.).
400V, dc . ,
,
.
1001000, 100 1000 .
3pF. 50. 50
(1pF) -
, .
-
(active probes), , FET. -
,
,
. ,
0.42pF,
( 4GHz).
100k10. , ,
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. 5. 81
.
.
10V,
10volt.
(differential
probes). (. 5.13), (floating) .
,
.
, .
.
(current probes). (. 5.13)
, ,
. AC,
AC/DC
. AC ,
2GHz. , AC/DC ,
Hall,
DC
100MHz. (split)
(solid).
.
.
() ()
. 5.13 (), : (1),
(2),
BNC (3) (4).
() , 100A (500A peak)
DC10MHz (1), 500A (700A peak) DC2MHz (2), 20A (50A peak) DC17MHz (3).Tektronix
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5.5 LISSAJOUS
,
.
, . . 5.14,
2V/div. 0.5ms/div.,
13 2 6VV = =
22 2 4VV = =
, 1/ 1/(8 0.5ms) 250Hzf T= = = .
o o o3360 360 1358
t
T = = = (5.9)
,
, Lissajous.
LissajousXY . XY,y
x.
siny yu V t= (5.10)
sin( )x xu V t = (5.11)
, y xV V=
, Lissajous. 5.15. 0180
, 90270, Lissajous.
V1
V2
t
T
2V/div.
0.5ms/div.
. 5.14 ,
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. 5. 83
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
10180
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
() () ()
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
() () ()
. 5.15 Lissajous
. : () 0180
, () 30
330
, () 60
300
,
() 90270
, () 120
240
, () 150
210
a b-
yx(. 5.16),
1 1sin siny x
y x
b b
a a = = (5.12)
ay
ax
by
bx
. 5.16
Lissajous
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. (5.12), -
(y x
V V ). , . (5.12) -
o o0 90 . ,
= o360 = . , . 5.15,
, o180 = ., siny y yu V t= , -
, sinx x xu V t = . Lissajous ,
/y x
. , ,
, . 5.17. uy
uxf, Lissajous
1/f.
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
() ()
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
() ()
. 5.17 Lissajous
sin(3 )yu t= , : ()o
sin( 15 )xu t= ,() osin( 30 )xu t= , ()
osin(2 0 )xu t= , ()osin(2 20 )xu t=
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. 5. 85
y, ux
Lissajous.
.
uy. ,
xu . , . 5.17, , uy
, ux ,
y x. , . 5.17,
/ 3 / 2y x = .
5.6 (DSO)
, .
. , ,
-
.
, . -
.
,
(). ,
.
, -
. , . ,
, .
(digital storage oscilloscopes, DSO),
-
.
DSO ,
-
, .
,
(A/D converters).
DSO A/D,
. (resolution)
bits ,
A/D.
. ,
.
, DSO-
.
DSO . -
, , DSO:
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86
, , ,
, , .
, -
(autoranging).
, , ,
, , DSO , FFT.
.
, -
. DSO-
RS232C GPIB (488). DSO
DOS format.
,
.
, -
, DSO-
, 50GHz.
, .
.
,
. , ,
, . ,
.
DSO, , -
, -. -
, . , DSO
, . ,
DSO. , -
(LCD).
5.6.1 DSO
, -
, -
. , . -
,
. . 5.18 DSO-
,
. ,
.
, .
3dB, 70.7%
.
Volts/div. -
, A/D.
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. 5. 87
Y
X
1234G
GDP
D/A
A/D-1
-11
A/D-2
-22
-
interface
:
Volts/div., Time/div. ..
R/W
R/Wtrig.
sampling
sampling
Volts/div.
Volts/div.
1
2
GPIB, RS-232C
Address
Bus
Data
Bus
X
Y
1
2
. 5.18 (DSO)
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A/D, -
DSO -
. A/D:
. -A/D, 05V, 010V, 5V +5V
10V +10V. , , .
.
, -.
, bits ().,
. DSO,
, A/D
(successive approximation A/D converters) (flash A/D converters).
, -
.
, 21 ,
.
Nbits.
-
,
.
,
sample and hold.
,
. DSO . 5.18 , . -
.
A/D
1GHz, 1ns.
A/D , DSO
CCD (Charge Coupled Device).
CCD , A/D
.
, CCD.
A/D
, . -
DSO. . 5.18
.
DSO. -
(digitizer) .
,
. ,
DSO,
DSO .
(graphics display processor, GDP), (D/A converter).
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. 5. 89
.
,
. -
(pixels) ,
. , 28= 256
29 = 512 , 217 = 131072 .
, bits
A/D. A/D 8bits, 28 = 256
, DSO
256 . 512 , -
512 . -
,
.
bits .
pixels , bit
, D/A.
256 byte
D/A8bits.
(GDP) ,
D/A
. -
.
. , -
. -
., DSO-
, . , -
, , -
. ,
, .
DSO, -
,
. interface . 5.18.
DSO,
DSO
. , DSO ,
.
,
,
. -
, -
. -
DSO. , -
,
.
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90
5.6.2
DSO
. ,
.
, -. , DSO
-
, . -
,
.
x(t)
. (. 5.19)
Fourier X(f), . 5.19,
fx. , -
, ( ), (.
5.19)
( ) ( )sk
s t t kT
=
= (5.13)
, Ts, . -
Fourier(. 5.19)
( ) ( )s s
k
S f f f kf
=
= (5.14)
-
. 5.20 . fs= 1/Ts,
. ,
xs(t) (. 5.19)
( ) ( ) ( )sx t x t s t= (5.15)
Fourierxs(t)
( ) ( )s s sk
X f f X f kf
=
= (5.16)
. 5.19
x(t) fs.
fs-
fx, x(t) ,
xs(t), (. 5.20).
fc, ,
x c s xf f f f (5.17)
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. 5. 91
()
t
t
t
s(t)
x(t)
xs(t)
()
() ()
() ()
()
f
f
f
f
Ts 2Ts 3Ts 4Ts
0-Ts-4Ts
X(f )
S(f )
Xs(f )
Afs
A
fs
0-fs
fs1
fs
-fs
0
0
0 fx
-fx
fx fc
-fx-fc
-fs
fsfs - fx fs + fx
LPF
Xs(f )
fs
>2fx
fs
2fx(), fs< 2fx()
xs(t). ,
, X(f).
, x(t) fx-
2s xf f , x(t)
xs(t) . (5.17).
2s xf f= Nyquist. Nyquist,
x(t), . 5.19. , x(t) xs(t)
, (aliasing). ,
fx 2s xf f< ,
(aliased sine wave) s x
f f .
s(t)
, s . (.
5.21), xs(t)
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92
s(t)
x(t)x
s(t)
fc-fc 0
1( )sf x t
(LPF)
. 5.20 x(t)
1
( ) ( ) ( ) ( ) 2 cos(2 )s o k sk
x t x t s t x t C C kf t
=
= = +
(5.18)
Fourier
( ) ( )s k sk
X f C X f kf
== (5.19)
, /o sC T= 0 sin( ) /s s sk kC f kf kf =
. (5.19) . (5.16) , -
Ck-
. fs.
,
.
fc
-fc 0
(LPF)x(t) xs(t)
s(t)
()
t
x(t)
f
X(f )
0 fx
-fx
0 fx
-fx
s(t)
xs(t)
()
Xs(f )
()
ff
c-f
c-fs fsf
s- f
xf
s+ f
x
LPF
-2fs
2fs
fs
>2fx
st
Ts/
x(t)Ts/
. 5.21 x(t), s(t) ,
fs(). () ()
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. 5. 93
1/ /o sC T = , x(t).
-
, Nyquist, -
fx, . -
fx
40dB .
5.6.3
DSO-
N bits A/D. ,
,
.
,
(interpolation) . - ,
. DSO
sin(x)/x.
fx, -
4.2s xf f= . , . , DSO10 ,
42, 512
.
sin(x)/x .
, DSO
. 5.22, .
,
fx (. 5.22).
sin(x)/x
, . sin(x)/x
,
fx. sin(x)/x
.
DSO -
. , ,
.
, DSO250MHz, 1GHz. ,
.
, . -
, fs
,
10sf =
(5.20)
, 10 .. (5.20) , -
.
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94
-1. 5
-1
-0. 5
0
0. 5
1
1. 5
()
-1.5
-1
-0.5
0
0.5
1
1.5
()
. 5.22 fx,
fs= 4.2fx() fs= 13fx(),
. 1GHz
50s/div., 500000 . -
, fs. 512 ,
fs= 1GHz 50ns/div.
DSO-
,
. ,
.
, -
(500000), (512).
, ,
scrolling-
.
DSO ,
, . ,
fs, ,
N1. ,
/ 2x sf f> . 1MHzsf = ( 0.01)MHzx sf kf= + 1, 2, 3k=
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. 5. 95
10kHz, -
. ,
,
.
5.6.4
DSO-
.
(real time sampling single shot sampling). -
.
fs,
fx, .
Nyquist 2s xf f , -.
, . ,
A/D,
(. 5.23).
(. 5.18),
. DSO
. ,
,
, .
, -
, fx.
, (equivalent time sampling).
Nyquist,
DSO.
,
(sequential sampling) (random
repetitive sampling).
(. 5.23). tk \k=1, 2, 3
tst, ( 1 0k k st st t t t t kt = + = + ). , .
.
tst,
,
.
. 5.23 ,
. -
, 10GHz, ,
. ,
DSO. -
, , -
(pretrigger view), .
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96
()
t
t0
()
0.0
()
t1=t
0+t
st
t2=t
1+t
stt3=t
2+t
stt4 t
5 t6
t7
t8
12 3 4
5
6
7
8
910
1112 13
14
15
tk
tst
t5
tk-1
0.0
0.0
t
t
t1 t
3
1
2
3
3
2
1
3
2
1
1
11
2
2
2
3
3
3
t2
. 5.23 (), ()
(). , . ,
DSO
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. 5. 97
t
0.0
. 5.24 ,
8.
,
,
, .
, . 5.23. ,
, .
,
(ta1,2,3 t1,2,3 t1,2,3). ,
.
, , .
-
.
, -
, . ,
.
VCOLPF
D/A
+ +
+
_
PLL
. 5.25 ,
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98
. ,
8, DSO
(. 5.24).
-
, . .
5.25. PLL (phase locked loop),
.
(VCO),
, .
PLL, ,
,
. D/A 8bits,
256 . D/A
,
DSO.
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