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Section
VI
Figure
6
-z
Model 5245L
02349
-L
o5245-B-il
2,3
tr
ufr
1.
6.
SAIVIPLE
RATE
a.
Controls pover to aII
circuits
except
crystal
oven
heater; max
cs\rr
turns
PCIMER
OFF.
b.
Controls time
between
measurements
from
0.2
sec
to
5
sec.
c.
Causes
display
to
HOLD indefinitely
when
murimum
g\p.
DC SIGNAL
INPUT provides
direct
coupling
to
internal amplifier
for
most measurements.
AC
SIGNAL INPIIT provides coupling
to
internal
amplifier through .022 ltt
(600
vdc maximum).
SIGNAL
INPUT SENSITIVITY
&
LEVEL control.
&.
Controls
input
attenuator; set
to highest
pos-
ition which includes
signal amplitude
(max
overload;
50v
in position
0.
1,
150v
in posi-
tion
1
;
500v
in position
10).
b.
Ma;rimum
CCW (CHECK
position) gives
in-
ternal self
check;counts
10
MHz
with selected
TIME-BASE gate
for
FREQUENCY;100 kHz
for
number of
periods averaged (10 psec to
1 sec)
for
PERIOD
A\IERAGE,
or
contin-
uously
at
selected TIME BASE
frequency
(0.
1Hz to
10
MHz)
for
MANUAL
START.
c.
Murimum CW (PLUG-IN position)
connects
outputof
plug-inunit
directly
to input
amplif
ier.
d.
The
LEVEL
control adjusts the
input
trigger
level
from
-0.
3V dc
to
+0.
3V
dc
when
atten-
uator
is
set
at
0. 1V
rms, from
-3.0V
dc to
+3.0Vdc
when
attenuator
is
set
at
1V rmgr
and
-30V dc
to
+30V
dc
when
attenuator is
set
at
10V
rms.
e.
Maximum counterclockrvise position
(PRE
-
SET) sets
trigger level
at zero volts.
GATE
lamp glows during counting (main
gate
open).
EXT
connector
a.
Provides input for higher of two frequencies
for
ratio
measurement (Iorver frequency
to
SIGNAL INPUT)
when
TIME
BASE
set
to
EXT.
b,
Provides
output
frequency
0.
1
Hz
to
1
MHz
as
selected
by
TIME-BASE switch
(see
text for
re
strictions)
.
TIME BASE selects either time that main
gate
is
on
for
frequency
or time
unit
per
count
for
period measurement.
B.
RESET pushbutton
returns
both displayed
and
internal
count
to
zero
when
pressed.
9.
FI]NCTION
a.
Permits totalizing
of pulses applied
to
SIG-
NAL INPUT when set to MANUAL
START;
holds accumulated
count
when switched to
MANUAL
stop.
b.
Permits
measurement of frequency applied
to
SIGNAL
INPUT during interval
selected
by
TIME-BASE switchwhen
in FREQUENCY.
c. Permits
period measurement
of
waveforms
applied
to
SIGNAL
INPUT
averaged over
1
to
100,000 periods when set
to
PERIOD
AVERAGE.
d.
Removes control
of TIME-BASE
and
FUNC-
TION switches when
set
to REMOTE
or
TIME
INT;
remote control
is
provided through
rear
connector
or plug-in
unit.
2.
3.
4.
7.
6-6
Figure
6
-2.
Operating
Controls (Front
Panel)
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