Tektronix 434, Instruction Manual, Page: 33 / 222

T im e D u ra tio n Measurements
T o measure tim e betw een tw o p o in ts on a w a v e fo rm , use
th e fo llo w in g p rocedure:
1. C o n n ect the signal to one o f th e in p u t co n n e cto rs.
2. Set th e V e rtic a l M ode s w itch to display the channel
used.
3. Set th e V O L T S /D IV s w itch to d isp la y a b o u t fo u r
d ivisio n s o f th e w a v e fo rm .
4. Set th e T R IG G E R IN G c o n tro ls to o b ta in a stable
d isp la y.
5. Set th e T IM E /D IV s w itch to th e fa ste st sweep rate
th a t displays less than e ig h t d ivisio n s betw een the tim e
m easurem ent p o in ts (see Fig. 2-9),
6. A d ju s t the v e rtic a l P O S IT IO N c o n tro l to move the
p o in ts betw een w h ic h th e tim e m easurem ent is made to the
center h o riz o n ta l line.
7. A d ju s t th e h o riz o n ta l P O S IT IO N c o n tro l to center
th e tim e-m easurem ent p o in ts w ith in th e center e ig h t d iv i­
sions o f the g ra ticu le .
8. Measure th e h o riz o n ta l distance betw een the tim e
m easurem ent p o in ts . Be sure the V a ria b le T IM E /D IV
c o n tro l is set to C A L .
F ig . 2 -9 . M e a s u rin g tim e d u r a tio n b e tw e e n p o in ts o n a w a v e fo rm .
O pe ra tin g In s tru c tio n s —4 3 4
9. M u ltip ly the distance measured in step 8 b y the
se ttin g o f th e T IM E /D IV sw itch .
E X A M P L E . Assum e th a t the h o riz o n ta l distance be­
tw een th e tim e m easurem ent p o in ts is fiv e divisio n s (see
Fig. 2-9) and th e T IM E /D IV sw itch is set to .1 ms.
Using the fo rm u la :
T im e D u ra tio n
h o riz o n ta l
distance
(divisions)
T IM E /D IV
se ttin g
S u b s titu tin g the given values:
T im e D u ra tio n = 5 X 0.1 nrs
T h e tim e d u ra tio n is 0.5 m illis e c o n d .
D e term in in g Frequency
T he tim e m easurem ent te ch n iq u e can also be used to
d e te rm in e the fre q u e n c y o f a signal. T he fre q u e n c y o f a
p e rio d ic a lly re c u rre n t signal is the recip ro ca l o f the tim e
d u ra tio n (p e rio d ) o f one cycle .
Use th e fo llo w in g p rocedure:
1. Measure the tim e d u ra tio n o f one cycle o f th e w ave­
fo rm as described in the previous a p p lic a tio n .
2. T a ke the re cip ro ca l o f the tim e d u ra tio n to d e te rm in e
th e fre q u e n c y .
E X A M P L E . T he fre q u e n c y o f th e signal show n in Fig.
2-9, w h ich has a tim e d u ra tio n o f 0.5 m illis e c o n d , is:
F requency =
1 1
tim e d u ra tio n 0 .5 ms
2 kH z
R isetim e Measurements
R ise tim e m easurements e m p lo y basically the same
te c h n iq u e s as tim e -d u ra tio n m easurem ents. The m ain
d iffe re n c e is the p o in ts betw een w h ich th e m easurem ent is
made. T h e fo llo w in g pro ce d u re gives th e basic m e th o d o f
m easuring rise tim e betw een th e 10% and 90% p o in ts o f the
w a v e fo rm .
1. C o n n e ct the signal to e ith e r in p u t c o n n e c to r.
2. Set the V e rtic a l M ode sw itch to d isp la y the channel
used.
2-19