Tektronix DC 501 Instruction Manual page 7

Operating Instructions—
DC
501
Fig, 1-2.
Two
examples of tnggaring
circuit
output showing
how
proper
adjustment
of
TRIGGERING LEVEL
control can avoid
an
errotteous
count.
The
DISPLAY TIME
control
sets
the length of time
a
measurement can be
held
in
the counter and displayed.
The
HOLD
detent
position allows a
measurement
to be
held
indefinitely, or
until
the counter
is
reset to zero
by
the
front-panel
RESET
button.
Count: Register capacity, 10^;
totalizes
events
accumu-
lated
between
start/stop
commarxfs from
front-panel
button.
INPUT
Frequency. 10
Hz
to
100
MHz;
sensitivity,
300
mV
peak
to
peak; triggering
level,
adjustable
±2V;
attenuator,
XI,
X5, X10,
or
X50:
maximum
input
voltage.
500V
(DC
+
peak
AC.
or peak
to
peak
AC)
at
1
kHz
or
less;
impedance.
(EXT
input),
approx
1
MH
paralleled
by about
20 pF
(INT
input)
approx
50n
paralleled
by
about 20 pF;
coupling,
AC.
INTERNAL TIME
BASE
Standard
Option
1
Crystal
Frequency
1
MHz
5
MHz
Stability
(0°C
to
+50*0.
after 1/2
hour
warm-up
Within
1
part
in
10®
Within
5
parts
in
10'.
Long-term
Drift
1
part or
less in
,
10®
per
month
1
part or
less in
10'
per
month
Accuracy
1
Adjustable
to
within
1
part
in
1
10'
Adjustable
to
within
5
parts
in
ICP.
INTERNAL
MEASUREMENT
INTERVAL.
Selectable
in
decade
steps.
Optional Features
Option 1—0.5 P/M
5
MHz
Crystal Oscillator.
The
DC
501
can
be ordered with
a
temperature-compensated
crystal oscillator to
provide
a
highly
stable
and
precise
internal
time
base
1-MHz
clock This option
includes
a
divide-by-five
1C counter
to
provide the proper output.
Measurement
Interval
Display
Units
Resolution
10
ms
000.0000
MHz
100
Hz
100
ms
00.00000
MHz
10
Hz
1
s
0000.000
kHz
1
Hz
10s 000.0000
kHz
0.1
Hz
Manual
0000000
(adds to displayed
number)
Option
2—
Automatic Gate
Control
and Readout
Scaling
Circuit.
This
circuit
automatically
selects
the
0.1-,
1-,
or
10-second
measurement
interval to display the largest
number
of
digits
without
overflow, and provides
the
appropriate
scaling of decimal-point and
units
lights to
produce
the correct
display. If
overflow
indication occurs,
the input signal
is
>
100
MHz
and
the
overflow
digit is
a
"
1
",
Accuracy, within
±
—
1
time-base accuracy,
total
count
DATA PRESENTATION
Visual
numerical readout, seven 7-segment
LED
with
automatically positioned decimal
point; units,
LED
irtdi-
caies
kHz
or
MHz;
overflow,
LED
indicates that readout
is
exceeded;
gate,
LED
irxf
icates
open
gate.
Electrical Characteristics
MEASUREMENT RANGES AND ACCURACY
Frequency; 10
Hz
to
100
MHz;
0.1
-s
to
10-s
counting
gate time; displays
kHz
or
MHz
units
with positioned
decimal
point.
Accuracy, ±1 counts
time-base accuracy.
DATA
INPUTS
and
OUTPUTS
Available
via
plug-in
connector
to 50-pin
connector
at
rear
of
Power Module.
Input
lines are available for signal
input, arxf internal
and
external
scan clock
control.
Output
lines are available for
BCD
output
(serial-by-digitl. and
to
indicate status of timing,
data good,
reset, scale,
decimal
point
and
overflow.
®1
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