Tektronix 7000 Series Manual page 6

1Α TI
M
I
N
G A
N
D
FRE
Q
UEN
CY
T he 7D14 Digital Counter an
d
t
he 7D15
U niversal Cou nter/Timer give you the
k
in
d
of versatility
t
hat lets you solve
to
d
ay's measurement
p
ro blems as well
as tomorrow's .
B
y combin ing one of
these co un ters with any 7000-Series
oscillosco
p
e, you obtai n greater flexi-
bility an
d
acc
u
racy
t
han is
p ossible with
eit her an oscillosco
p
e or α co unter
alone. The counter gives you digital
accu
r
acy an
d
resolution, wh ile the os-
cillosco
p
e lets you see what the cou n -
ter is triggeri ng on . The visual
d
is
p
lay
re
d
uces errors, s
p
ee d s up meas ure-
The 7D14 Digital Counter an
d
t
he 7D15 Universal Counter/Time r
ment time, an
d
allows you to ma ke α
greater variety of meas urements. This
combinatio n also ma kes
p
ossible the The following section
d
escribes the counter. The T RIG SO UR C E positions
u niq ue feature of oscillosco
p
e co n-
p
ur
p
ose a n
d
o
p
eratio n of some of t he of th e INPUT SEN S (7D14) an
d
t
he Ρ-Ρ
trolle
d
trigger armi ng.
W
it h trigger arm- basic controls on the 7D14 an
d
7D15, SEN S (7D15) switch es select this inter-
ing you can visually select specific time to
h
el
p
you better u n dersta n
d
t
he full
παΙ trigger source mo
d
e. T h is signal in-
intervals for meas urement with in α re- measurement ca
p
ability of the units.
p
ut metho
d
re
d
uces circuit loa
d
ing an
d
p
etitive or non-repetitive
p
ulse trai n. Following this General O
p
eratio n sec-
p
rovi
d
es
p
re-conditioni ng of the in
p
ut
Cou nter/oscillosco
p
e measurement tion is α series of detaile
d ap
plications, signal .
systems
h
ave
p
rove
d
invaluable to en-
whic h
illustrate t he measureme nt of
Trigger level
p
reset is also available on
gi neers an
d d
esigners in
d
igital elec- bot h time an
d
frequency p arameters
both units. Wit h
t
he 7D14, the
p
reset
tronics, com
p
uter electronics, in
d
ustrial suc h as wi
d
th,
p
erio
d
,
p
ro
p
agation
d
e-
level can be set wit h α front-
p
anel,
controls, communications an
d
ma ny lay, frequency, etc . Eac h
app
lication
screw
d
river a
d
ju stment . Wh en the 7D15
ot her fiel
d
s. i ncl u
d
es an e
q
ui
p
ment setu
p
illustra-
TRIGGER LEVEL co ntrols are set to
Bot
h
t
he 7D14 an
d
7D15 measure fre-
tion an
d
α cookbook ty
p
e
d
escri
p
tion
PRESET, the unit automatically triggers
q
u
ency an
d
eve
n
ts, ma kin g them i n-
of the
p
ro
p
er control settings .
at th e 0 volt level. In th is
p
osition you
valuable tools wh en working with CW
can also set the trigger level extern ally
or freque n cy
b
urst signals. Th e 7D14
eneral
et
eration
(see the following
d
iscussion) .
g p
measures frequency
d
irectly to 525
MH z; the 7D15 measures freq uency up
to 225 MH z. Triggering .
T
he trigger selectivity of t he
The 7D15 can also
p
rovi
d
e you with
7D14 an d 7D15 contributes greatly to
timing measurements with α high
d
e-
the measu
r
ement flexibility of these
gree of accuracy (0 .5
pp
m) an
d
resolu-
units.
B
ot h units
p
rovi
d
e oscillosco
p
e
tion . Α sim
p
le touc h of α button selects
ty
p
e trigger co ntrols, wh ic h allow the
the measurement re
q
uired, suc h as
choice of AC or DC cou
p
ling, + or -
period, pulse w idt
h
, or time inte rval.
slope, i nter n al or extern al trigger
U
sing the
d
elaye
d
swee
p
of your time
source, an
d ad
j ustable trigger level.
b
ase, you can externally arm the trigger
These controls are located in the green
circuits whic h allows you to visually
s hade
d
areas of eac h
p
lug-in . Το obtain
Trigger
L
evel
J
ac ks.
T
he 7
D
15 pr ovides
select the ti
m
e interval you want mea-
α trigger signal, the signal to be mea-
two front-panel T RIG LEVEL jac
k
s. T he
sured. Now you can see if you are false
sured is generally in
p
u t d
irectly into the
voltage that a
pp
ears at these j ac ks is
triggeri ng on
n
oise or even measuring
counter th roug h α front
p
anel signal in-
p
ro
p
ortional to th e actual voltage levels
t h e wrong time inte rval.
p
ut connector. Wit h the counter in α
at wh ic h
t
he trigger circuits (Α and Β)
h
orizontal
p
lug-in com
p
artment,
h
ow-
have
b
een set to trigger. Table 1 lists
ever, you can ro ute α sig nal from α ver-
the actual trigger level ranges of the
tical am
p
lifier
p
lug-in internally t h roug h
trigger circ u its for the three p
ositio ns
th e oscillosco
p
e mainframe to t h e
of t he Ρ-Ρ SEN S co ntrols an
d
t
h e
corres
p
on
d
ing out
p
u ts at th e T R IO
LEVEL jac ks. Note that for all th ree trig-
ger level ranges, th e out
p
ut of the TR IG
LEVEL jac ks is from -0 .5 V to +0 .5
V.