Racal Instruments 9901 Maintenance Manual page 12

1
.
GENERAL
II
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Model
9901
is
a
6
digit
50
MHz
Ajforanging
Universal Counter
Timer.
2.
MEASURING FUNCTIONS
Modes
of Operation:
Frequency (Manual), Frequency
(Autoranging),
Single and
Multiple
Period, Single
and
Multiple
Ratio,
Single
and Double
Line Time
Interval,
Single
and Double
Line
Time
Interval
Averaging;
Totalizing.
3.
DISPLAY
4.
Format:
Latch:
Six digit in-line,
LED
seven segment
display.
Decimal
point automatically positioned.
The
display
is
latched
for
Frequency,
Period
and
Ratio measurement and
automatically unlatched
in
all
other modes.
Overflow
Indicator:
Gate
indicator:
Display Time:
A^asurement Check:
Segment Check:
Reset:
LED
ill
uminated
when
overflow
occurs.
LED
ill
uminated when
gate
is
open.
Gate
time
plus 0.25s
in
Frequency,
Period
and
Ratio modes.
2.0s
in
other modes.
A
switched
hold
position
is
provided.
Counter
reads
1
Mtiz.
Sets
display
LED's
to 8
when Check and
Reset
selected.
Manual
by push-button,
or automatic.
CHANNEL A
INPUT - A.C. COUPLED
Frequency Range:
10
Hz
to
50
MHz.
Sensitivity: lOmVr.m.s.
Maximum
Input Level: 250V
r.m.s. up
to
10 kHz.
50V
r.m.s. up
to
100 kHz.
lOV
r.m.s. above lOO kHz.
400V
d.c.
9901 Vol.2
Tech. Spec
(1)