Advertisement
Section
1—
DC
501
OPERATING INSTRUCTIONS
DC
501
General Description
The
DC
501 100
MHz
Counter measures frequency from
10
Hz
to
100
MHz,
and
totalizes
(counts
number
of events)
from 0
to
10'
at a
maximum
rate
of
100
MHz.
Seven
7-segment
light-emitting
diodes (LED's) provide
a visual
numerical
display.
The
decimal
point
is
automatically
positioned
and
leading
zeros
(to
the
left
of
the
most
significant
digit
or
decimal
point)
are
blanked.
Digit
overflow
is
indicated
by
a
front-panel
LED.
Signals to
be
counted
can be
applied
via a
front-panel
BNC
connector
into
an
impedance
of
1
MO
and 20
pF
or
via
the
rear
connector
into
an
impedance
of
about 50
O
and
20
pF.
The
DC
501
is
designed
to
operate
in
a
TM
500-Series
Power Module
only.
Preparation
The
DC
501
is
ready
for use as
it is
received.
To
install,
align
the
upper and
lower
rails
of the
DC
501 with
the
plug-in
compartment
tracks of the
power
module, and
insert
it
fully.
To
remove,
pull
the
release latch
to disengage
the
DC
501 from
the
power
module. Connect
the
power
module
cord
to
a
suitable line-voltage source.
Basic
Operation
NOTE
Refer
to
the
Controls
and
Connectors
pullout page.
Also, additional information
is
given
later in this
section.
Display
Check.
Press
the
RESET
button
to
check
the
7
character
segments
of each
digit;
the numerical display
should be
a
row
of
eights.
To
check
the decimal point
position
and
the
units indicators,
set
the
ME
ASU
REM ENT
INTERVAL
switch
as follows:
Switch
Position
Numerical Display
Units
.01
SEC
.0000
MHz
.1
SEC
.00000
MHz
1
SEC
.000
kHz
10SEC
.0000
kHz
MANUAL
000
In
the
MANUAL
position,
no
decimal
point
will
be
displayed. Press the
START
button and check
that the
GATE
indicator
lights,
then
release
the
button (STOP) and
check
that
the
GATE
light
goes
out.
To
check
the
OVERFLOW
indicator,
set
the
MEASUREMENT
INTER-
VAL
switch
to
10
s,
the
INPUT
switch to
EXT,
and apply
a
15- or
20-MHz
signal
to the
INPUT
connector.
The
length
of
time
a
display
can
be
held
is
determined by
the
DISPLAY TIME
control,
and
will
be
discussed
in
the
next
few
paragraphs.
Frequency Measurements.The
DC
501
provides
direct
measurement
of the average
frequency
of
signals
from
about 10
Hz
to
100
MHz. The
input
sensitivity
is
300
mV
peak
to peak, so
select
the
proper attenuation (XI,
X5,
X10,
or
X50)
for
the given
signal.
Other
input
character-
istics
are
given
on
page
1-3.
The
input
signal
must
not exceed
500
volts.
Set the
INPUT
switch to
EXT
and
apply
a signal
to the
INPUT
connector. Set
the
MEASUREMENT
INTERVAL
switch to the
.01
SEC
position
and
observe the numerical
readout
display.
Adjust
the
TRIGGER LEVEL
control for
a stable reading.
The
zeroes leading the
most
significant
digit
in
the display should
be blanked.
Then
turn the
MEASUREMENT
INTERVAL
switch
to the position that
gives
the
desired
reading.
Generally,
use
the
shorter
measurement
intervals for
high-frequency, low-resolution
measurements and
longer
intervals
for
measurements
re-
quiring
a
high
resolution.
For
instruments having the
Automatic Gate
option, the
measurement
interval
is
selec-
ted automatically
when
the
MEASUREMENT
INTERVAL
switch
is
set
to the
AUTO
position.
NOTE
The
OVERFLOW
indicator
can
be
lit
for high-
resolution
measurements,
allowing
the
frequency
to
be
indicated
to
0.
1
Hz.
Refer
to
the
Electrical
Characteristics at the
end
of
this
section for
resolu-
tion
and
accuracy
at
each position
of
the
MEASURE-
MENT
IN
TER VA
L
switch.
The
display
is
updated
at a rate
determined
by
the
DISPLAY TIME
control.
Each time
a
sample
of the input
signal
is
taken, the
GATE
light will
flash
and
the
new
Advertisement
Need help?
Do you have a question about the DC 501 and is the answer not in the manual?
Questions and answers