Tektronix 7000 Series Manual page 7

F or t h e 5 V and 50 V ra nges, th e TR IG co u nter to ma ke
h
ig hly accurate mea- F ig . 1 shows an exam p le of the mea-
LEVEL output is thus
p
ro portional to sureme nts on selected portions of α surement of the time betwee n two non-
h e actual trigger level voltage. Usi ng α re petitive or non-repetitive pulse trai n. ad j acent
p
ulses,
u
sing trigger arming .
VM to monitor the voltage at one of
F ew ot h er counters offer th is feature .
In th is case, both
t
he chann el Α an d Β
th ese jac ks, you can set the respective
Since the counter is being used in an
trigger controls are set to trigger on the
trigger circuit to trigger on an exact
oscillosco pe, the
d
elayed swee p gate,
50% level of the
p
ositive-going slope
voltage level.
F
or exam p le, if you want
whic h is readily availa ble from the time
of α
p
ulse . The
d
elayed swee p gate of
to set the Α TR IGG ER LEVEL to trigger
base, ma kes α very co nvenient external
the oscilloscope is use d as the armi n g
on th e +2 .5 V level of the Α
i
np ut sig-
armi ng signal for the co unter . The
d
e-
gate, and must be connecte d to
b
ot h
ηαΙ, then measure + 0.25 V with α DVM
laye d swee p gate is
p
articularly useful,
the Α ARM an d
t
he Β
A
RM co nn ectors .
at Α TR IG LEVEL OU TPU T. This also
beca use
b
ot h
t he wi d t h a n d
t
h e ti me
Usi ng the oscillosco pe Delay Time ΜυΙ-
means that you need to be on the 1 Ρ-Ρ
p
osition (delay) of th is gate can
b
e con-
ti plier a n d th e Β swee p Time/Divisio n
SEN S range . This feature is hel pful
trolle d with
t
he time base Time/ Division
controls, th e
d
elayed swee p gate can
wh en trying to measure α parameter li k e
co ntrols an d
t
he Delay Time
M
ulti plier
be adj usted to select the specific
p
ulses
risetime or
p
ulse wi dth, where trigger
co ntrol, respectively. The gate also cor-
to
b
e measured.
level is critical,
respo nds to the intensifie d zone that is N ote th at when using trigger arming,
Ρ- Ρ
Trigge r Level TRIG LEVEL
Th e arming signals are in put i nto the
tells t he trigger circuits w hen t hey
7D15 th ro ugh the Α
A
RM an d Β AR M
s
hould begin looki ng for th e selected
0.1
- 0.5 ν to + 0.5 ν - 0.5 ν to + 0.5 ν
start and stop meas urement points.
-5 ν to +5 ν -0 .5V to +0.5V
co nn ecto rs. An arming gate am p litu de
. The
10 -5 ο ν tο +50V - ο.5 ν to + ο.5 ν
of greater than 0.5 V (α hig h) arms
settings of the trigger controls
d
eter-
ch ann el Α an d an am plitu de of less than
mine th e exact trigger
p
oi nts an d
t
hus
0.2 V (α low) arms c h a nn el Β. Wh en
the measurement interval .
S
EN S
R
ange Output
table 1
TR IGG ER LEVEL RANGES
seen on the CRT in the Α Intensified By
t
he arming gate does not affect the ac-
Β swee p mode . curacy of the measurement. It merely
chan nel Α is arme d, the counter starts
- -
---
counting as soon as the channel Α trig
Wh en on e of the TRIGGER LEVEL con- ger con ditions are met; when c hannel
trols is set to PRESET, the trigger cir-
Β is arme d, the counter stops cou nting
cu it automatically triggers on the 0 V
as soon as the c hannel Β trigger co n d i-
10
level of t he signal . In the PRESET
p
osi-
tions are met .
tion,
h
owever, you can also set the trig-
ger level extern ally, by i nputi n g α volt-
Ι
Ι
age level throug h
t
he respective TRIG
Ι Ι Ι
LEVEL jac k. As wit h
t
h e output voltage
Ch Α Trigger Ι
C
h Β Trigge r
of th e TR IG LEVEL j ac k, the i nput volt- Ί
FIL
age range of the
j
ac ks is also -0 .5 V
P
u lse Train
to +0 .5 V . T he setting of th e Ρ-Ρ SEN S
Ι
Ι
F1
switc h agai n sets th e trigger level
ra nge, an d you in put α voltage that is Ι Ι
Ι
Ι
p
ro portio nal to the
d
esired trigger level
Delaye d Swee p Gate
voltage.
F
or exam ple, if α +15 V trigger
Ap p lied to bot h Ι
level is
d
esired, set th e Ρ-Ρ S EN S switch
Α ARM
a
nd Β ARM Ι Ι
to 10 V (t he 50 volt ra n ge) an d apply α Ι Ι Ι
DC voltage of +0 .15 V to th e TRIG
LEVEL jac k.
Pseudo Gate (Actual
Ι Ι Ι
Time Interval Ι Ι
M
easu red) Ι j
. TRIG Ι
Ι
Ι
Ι
LEVEL
,¬ ~
Ι
ι
ι
ι
Β
ARM
Selective Trigger Armi ng.
A
nother
u
se-
ΜυΙ feature
of t h e 7D15 is t
h
e ability to
m
xternally arm t
h e co
u
nte
r
trigger cir
cuits .
Th is gives you external control
of t he measurement interval,
b
ut more
im portant, it allows you to use th e
Ch Α is Armed
Ch B is Armed
Count starts and slope Co unt stops and slope
F
ig . 1
M
easuring the time interval between two
non-adjacent
pu lses usi ng trigge r
225 MH z UNIV ER
armi ng.
G0 U ΝΤΕ
R
/ΤΙ Μ 1
_ - ___,
5