R Isetime M Easurement; Time Difference Measurements - Tektronix 5440 Instruction Manual

O
perati
n
g Information-5440
R
isetime
M
easurement
E
XA
MPLE :
Assume t
h
at t
h
e
h
orizo
n
tal dista
n
ce
R iseti m e measureme n
ts em
p
loy basically t h
e same
betwee
n
t
h
e 10 ο/ο a
n
d 90 ο/ο p oints is four d ivisions a nd
t
h
e
tec
hn
iques as t
h
e time-
p
eriod measurements . T h
e mai
n
Sec/Div switc
h
is set to 1 μs .
d ifference is t
h
e poi n
ts between w
h
ic
h
t
h
e measurement is
Using t
h
e p erio d formula to fin d risetime :
ma
d
e . T
h
e following proce d u
r
e gives t
h
e basic met
h
od of
measuring risetime betwee n
t
h
e 10%a nd
90ο % ο p oi
n
ts of t
h
e
R
isetime
η istance 1 Sec/Div
waveform . = d Χ switc
h
= (4) (1 μ s) = 4 μ s
p eriod
(divisio
n
s)
setti
n
g
1 . Co
nn
ect t
h
e sig
n
al to t
h
e input co
n
nector .
T
h
e risetime is 4 microsecon d s .
2 . Set t
h
e
V olts/Div switc
h
and variable
V olts/Div
Time Difference M
easureme
n
ts
co
n
trol to p roduce α dis p lay exactly five d ivisions in
When use d in con
j
uction wit h
α calibrate d time-base
am p lit u
de .
plug-i
n
unit, t
h
e multi-trace feature of t
h
e 5400-series
oscillosco
p
e
p
ermits measurement of time d iffere n
ce
betwee
n
two or more separate events . To measure time
3 . Ce
n
ter t h
e dis p lay about t
h
e ce
n
ter
h
orizontal line
differe
n
ce, use t h
e following p rocedure :
wit
h th
e vertical P
ositio
n
control .
4 . Set t
h
e time-base triggeri
n
g controls to obtain α
stable dis
p
lay . Set t h
e Sec/Div switc
h
to t
h
e fastest sweep
2 .
Set t
h
e Display switc h
on t
h
e time-base unit to eit
h
er
rate t
h
at will d is
p
lay less t
h
an eig
h
t divisions betwee
n
t
h
e
Chop or Alt . In general, C
h
o
p is more suitable for low-
10%
a n
d 90 ο / ο p oints on t h
e waveform (see
F
ig . 1-9) .
fre q uency sig
n
als . M ore informatio n
on d etermining t h
e
5 . A
dj
ust t
h
e
h
orizo
n
tal
P
ositio
n
control to move t h
e
10 ο/ο poi
n
t of t
h
e waveform to t h
e seco
n
d vertical li
n
e of t
h
e
gratic
u
le .
6 . M easure t
h
e
h
orizo
n
tal distance between t h
e 10 ο/ο
a
n
d 90 ο/ο points . B e sure t
h
e variable Sec/Div control is i n
th
e Cal p osition .
7 . M ulti p ly t
h
e dista
n
ce meas
u
re d
i
n
ste p 6 by t h
e
setti
n
g of t
h
e Sec/Div switc h
.
1- 1 6
90%
P
oi
n
t
} ~
P
oi
n
t '
Ί
Ι
Ι
~
1
Horizontal ,~
1
d
ista
n
ce
F
ig . 1-9 .
M
easu
r
i
n
g
r
isetί me .
1 . Set t h
e in p ut coupli
n
g switc
h
es of t
h
e am
p
lifier
c
h
a
n
nels to eit
h
er ac or d c .
mode is given u
n
der
V
ertical Dis p
lay M o
d
e i
n th
is sectio
n
.
3 . Set t
h
e vertical pl
u
g-in triggering switc h
es to trigger
t
h
e display οη Channel l (orleft p lug-i n
)a
n
dChannel 2(or
ce
n
ter p lug-in) .
4 . Co
nn
ect t
h
e reference signal to t h
e C
h
annel 1 i
n
put
con
n
ector a
n
d
th
e com
p
ariso
n
signal to t h
e C
h
annel 2 (or
center p lug-in) in pu
t con
n
ector . T
h
e reference sig
n
al
s
h
ould prece
d
e
d
t h
e compariso
n
signal i
n
time . U se
coaxial cables or probes w
h
ic
h h
ave similar time-delay
c
h
aracteristics to connect t h
e sig
n
al to t
h
e in p ut connec-
tors .
5 . If t h e sig n als are of o
p
p osite polarity, i n vert th e
Ch
a
nn
el 2 (or center plug-i
n
) display . (Sig n
als may be of
opposite polarity d ue to 180°
ph
ase differe
n
ce ; if so, ta
k
e
t
h
is into account in t h
e final calculation .)
6 . Set t h
e V olts/Div switc
h
es to p roduce about four
divisions of
d
is p lay waveform .
7 . Set t
h
e time-base triggeri
n
g controls for α stable
dis p lay . Set t
h
e Sec/Div switc
h
for α sweep rate w
h
ic
h
sh
ows t
h
ree or more divisio n
s betwee
n
t
h
e measureme
n
t
p
oi
n
ts, if p ossible .
8 . Ad
j
ust t
h
e vertical
P
ositio
n
co
n
trols to b ri
n
g t
h
e
measurement
p
oi
n
ts to t
h
e ce
n
ter
h
o
r
izo
n
tal reference
line .