Frequency Measurement - Racal Instruments 9901 Maintenance Manual

5
.
Input
Impedance:
1
Mfi
in
parallel
with approximately
25pF.
CHANNELS A
& B -
D.C.
COUPLED
6
.
Frequency Range:
DC
to
10
MHz,
Sensitivity:
±
0.25V about
+1V
nominal
or
contact
closure
to
earth
.
Maximum
Input Level:
Pulse Duration:
Input
Impedance:
FREQUENCY MEASUREMENT
± 35V.
50
ns
minimum
at trigger points.
Approximately 10 kCi
(Falling to
IkQ above
approximately +5V).
7.
Input:
Frequency Range:
Coupling:
Channel A.
DC
to
50
MHz
(direct).
AC
or
DC
Gate
Times:
Manual:
1
ms
to 100s
in
decade
steps.
Automatic:
Gate
times up
to
Is
are selected
automatically
to
avoid
overspill.
Designed
hysteresis
avoids undesirable range changing
at
small frequency
deviations.
SINGLE &
MULTIPLE PERIOD
MEASUREMENT
Input Channel: Channel A,
Range:
1
ps to Is.
Clock
Unit:
1
ps.
Coupling:
AC
or
DC
Periods Averaged:
5
1
to
10
in
decade
multiples
Accuracy: ±
0.3%
±
Freq.
standard
Number
of periods
averaged
accuracy
(at
50
mV
r.m.s. a.c.
input with
40 dB
S/N
i
Bandwidth:
Automatically reduced
to
10
MHz
(3
dB)
when
Period selected.
o
9901 Vol.2
Tech. Spec.
(2)