Tektronix 7A16A Instruction Manual page 11

Comparison M eas
u
rements
T
h
is is t
h
e vertical conve
r
sion factor .
In some app licatio
n
s it may
b
e
d
esira
b
le to esta
b
lis
h
u nits of m easurement ot h
er t
h
an t
h
ose indicate
d b
y t
h e
V O
L TS/DI V
switc
h
. T
h
is is partic
u
larly
useful w
h
en
com p aring un
k nown signals to α reference amplitu de . One
use fo
r
t
h
e compariso
n
-measureme
n
t tec
hn
i que is to facili-
tate calibratio
n
of e
qu
i
p
ment w
h
ere t
h
e d esire d
a
mp
litu d e
d
oes not prod
u
ce an exact number of d ivisions of d eflec-
tio
n
. T
h
e a d
j
ustment will be easier an d mo
r e accurate if
ar
b
itrary units of measurement are esta
b
lis
h
e d , so t
h
at t
h
e
correct a d
ju
stme
n
t is i nd icate
d b
y an exact
numb
er of
d ivisions of d eflection . T
h
e following
p
roced
u
re
d
escri
b
es
h ow to establis
h
ar
b
itrary u
nits of meas
u
re for com
p
arison
measurements.
To esta
b
lis
h
α ve
r
tical d eflection factor
b
ase
d
upon α
s
p
ecific reference amplitu
d
e, proceed as follows :
2 . Set t
h
e V O
L
TS/DI V
switc
h
an d
t
h e V A
R
IA
BLE
co
n
trol to
p ro d uce α d is p lay w
h
ic
h
is an exact number of
ve
r
tical
d
ivisio
n
s in am p litu d e . Do
not
c
h
a
n
ge t
h
e
V A
R
IA
BLE
co
n
trol after o
b
tai
n
ing t
h
e desire
d d
eflection .
V ertical
Conversion
F actor
Ope
r
ation-7A16A
_
reference signal am
p
litu d e (volts)
vertical
d eflection Χ V O
L
TS/DI
V
( d ivisions)
setti
n
g
5 . To measure t
h
e am p litude of an un
k
nown signal,
d
isco
nn
ect t
h
e refe
r
e
n
ce sig
n
al a
nd
co
nn
ect t
h
e unknown
signal to t
h e I
np
ut co
nn
ector . Set t
h
e V O
L
TS/DI
V
switc
h
to α setting t
h
at
p rovides s
u
fficient vertical deflection to
ma
k e an accurate meas
u
rement . Do not re-a d ju st t
h
e
VA
R
IA
BLE control .
6 .
M
eas
u
re t
h
e vertical deflection in
d
ivisions and
calculate t
h
e am p litu de of t
h
e
u
n
k
nown signal using t
h
e
following formula :
Signal _ V O
L
TS/DI
V
vertical vertical
1 . Co
n
nect t
h
e reference signal to t
h
e In
pu
t co
n
nector .
Am p
lit
u
d e setting
Χ conversio
n
Χ
d
eflectio
n
Set t
h e time-base sweep rate to d isplay several cycles of t
h
e
factor (divisio
n
s)
sig
n
al .
E XA
MPLE :
Assume α reference signal amplit
u
d e of 30
volts, α V O
L
TS/DI
V
setting of 5
V
a
nd
t
h e V A
R
IA
BLE
control a d
j
usted to
pr
ovi
d
e α vertical
d eflection of four
d
ivisions .
S
ub
stit
u
ting t
h
ese values in t
h
e vertical co
n
version factor
formula (step 4) :
3 . To esta
b
lis
h
an arbit
r
ary ve
r
tical
d
eflectio
n
factor so
t
h
e am
p
litu
d
e of an
u
n
k
nown signal can
b
e m easure
d
V
ertical Conversion -_ 30
V
=
1 .5
accurately at any setti
n
g of t
h
e V O
L
TS/DI
V
switc
h
, t
h
e F
actor 4 Χ 5
V
am
p
lit
u
de of t
h
e reference signal must be
kn
own . If it is
not
kn
own, it ca
n b e m eas u
re d
b
efore t
h
e V A
R
IA
BLE
control is set in ste
p
2 .
T
h
en wit
h
α V O
L
TS/DI
V
setting of 2 V, t
h
e
p
ea
k
to
p
ea
k
am
p
lit
u
de of an unknown sig
n
al w
h
ic
h
p
r
o d uces α vertical
d eflection of five d ivisions can
b
e
d
etermi
n
ed by using t
h
e
4 . Divide t
h
e am
p
lit
u
de of t
h
e reference signal (volts)
signal am
p
litu
d
e fo
r
mula (ste
p
6) :
b
a
r
t
h
e product of t
h
e vertical
d
eflection ( d ivisions)
establis
h
ed in step 2 an d
t
h
e setting of t
h
e V O
L TS/DI V
Signal
switc
h
. Am plitu d e
2 V Χ 1 .5 Χ 5 =
15 volts