Tektronix 2235 - A Sweep Logic; ALTERNATE Β SWEEP

F req uen cy
T h
e
fr
e que
n
cy of α r ec u rrent signal can be dete r mi ned
f r om its time- du ration
meas urement as follows :
1 . M easure t h e time
du
r
atio
n
of one waveform cycle us-
ing t he pr ecedi ng "Time D u ration"
measurement pr ocedu r e .
2 . Calculate
t
h
e reci p rocal of t h e time- du ration value to
dete r mi n e t h e fre qu
ency of t
h
e waveform .
E XA
MPLE : T h e signal in F ig ure 4-6 h as α ti m e du r atio n
of 16 .6 ms .
Calculati n g t h e r ecipr ocalof time du ration :
F re q uency =

1

=

1

=
60
Hz
time du ratio n 16 .6 ms
Rise Time
EMEEMOMEM
®EREM ®®®®
' ®® ®~~~
MENOMONEE
W ®~®
1
HOR IZO N TA L
DISTA N
C
E
C4 το 7-16 Ι

h
orizo
n
tal

Α S E C/DI V
dista nce χ switc h
Figure
4-6 . Ti m e
d ur atio n .

R ise Time
=
(divisio
n
s)

sett i ng
magnification
factor
R ise-time meas urements u se t he same met h
ods as time
du r atio n , exce p t t h at t he measurements are
made betwee n
t he 10% and 90% p oi n ts of t he low-to-high transition
of t
h
e
selecte d waveform (see Fig u re 4-7) . F all time
is meas u re d
betwee n t he 90% an d 10% points of t h e
high-to-low transi-
tion of t h e wavefo r m .
1 .
Preset i n str u ment controls
a
n
d o b tain α baseli n e
trace . En sure t h at t h e BW L I M IT is off (
bu tton out) .
O pe r ati ng Pr oce dur es-2235 ΑΝ / US M -488 O p
e
r
ato
r
s
MEN
:
MEN
M FIE 1 1 --- 1002
ιιιωιιι . ιιιωιιιω
AMPLITUDE
= ΝΟΝΕ
®®
H
O
R
IZO N TA L
DISTA
N C E
Fig ur e 4-7 . R ise time .
C4207 -i
3 . Set t he appropriate V
O LTS/DI V switc h an d V ariable
control fo r an exact 5- d ivision
d is p lay .
4 . V e r tically p osition t h e trace so th at t h e zero reference
of t h e waveform touc h es th e 0% ο graticule line and t h e to p of
t he waveform
to uc
h
es t
h
e 100% graticule li ne .
5 . Horizo n tally position t he d isplay so t he 10% p oint on
t he waveform
intersects t h e second vertical g r aticule li ne .
6 . M eas u re t h
e
horizontal
d istance b etween t he 10%
an d 90% ο points
(between
Points Α
a
n
d Β of F igu r e 4-7) a nd
calculate t
h
e time du r atio n usi n g t he followi ng fo r m u la :
E xam p
le :
T h
e
h orizontal
dista
n
ce betwee n t he 10%
ο
a nd
90%
ο p
oi
n
ts is 5
divisio n
s, an d t he ΑSE C/DI V switc h is
set to 1 us per
d
ivision . Α
magnification factor of 1 is
u sed .
Su b
stit
u
ting
t
h
e
given val
ues in t h e formula :
R ise Time
=
5
div χ 1
μ s/ d
i ν
=
5
μ s
Time Differe n
ce
B
etwee
n
Pu lses onTime- R elated
2 .
Apply an exact 5- d ivision sig n al to eit h
er vertical-
Sig n
als
c
h
a
nn
el i npu t connector and set t he VER
TICA L M OD E

T h
e calibrated swee p s p eed and d ual-t r ace featu r es of
switc h to d
isplay t he ch a nn el use d .

t h
is inst
r
ume
n
t allow measu r eme n t of t he time d iffere n ce