Fluke PM6690 Service Manual page 15

– Press INPUT A and select
input impedance.
– Connect the LF synthesizer to Input A. Use the follow-
ing settings (into 50 W):
Sine, 10 kHz, 0.9 V , and +0.50 V
PP
– Verify that the three modes for the trigger indicator are
working properly by changing the trigger level:
– Press the
Trig key and enter +1 V via the keyboard,
then verify by pressing
indicator according to Table 2-4.
– Press the key and enter –1 V via the keyboard
Trig
by pressing the key, then verify by pressing
±
. Check the trigger indicator according to
EXIT/OK
Table 2-4.
– Press the
key and enter 0 via the keyboard, then
Trig
verify by pressing EXIT/OK
tor according to Table 2-4.
– Apply the signal to Input B instead.
®
– Press
MEAS FUNC Freq
– Press and select
INPUT B
W input impedance..
50
– Repeat the trigger level settings above to verify the three
trigger indicator modes for Input B.
Input Controls
– Recall the DEFAULT settings.
– Connect the LF synthesizer to Input A. Use the same
settings as in the previous test.
– Press INPUT A and select
– Press .
EXIT/OK
– Check the V and V
max min
according to the first row in Table 2-6.
– Perform the rest of the settings in sequence, and read the
corresponding V and V
max
these values are approximate and serve only as indica-
tors of state changes.
Settings V
max
INPUT A, DC, 50 W
+950 mV
+450 mV
AC
+0.45 V
10X
>+0.45 V
1 MW
Table 2-6
Input controls check.
– Connect the generator to Input B.
®
– Press MEAS FUNC Freq
– Press and select
INPUT B
– Press EXIT/OK .
– Check the V and V
max min
according to the first row in Table 2-6.
– Perform the rest of the settings in sequence, and read the
corresponding V and V
max
MAN ual trigger level and
.
DC
Check the trigger
EXIT/OK.
. Check the trigger indica-
® ®
Freq (A) B
ual trigger level and
MAN
W.
DC and 50
voltage levels on the display
values. Remember that all
min
V Pass/Fail
min
Input A Input B
+50 mV
-450 mV
-0.45 V
<-0.45 V
® ®
Freq (A) B
W.
and
DC 50
voltage levels on the display
values.
min
W
Reference Oscillators
50
X-tal oscillators are affected by a number of external condi-
tions like ambient temperature and supply voltage. Aging is
also an important factor. Therefore it is hard to give limits for
the allowed frequency deviation. The user himself must de-
cide the limits depending on his application, and recalibrate
the oscillator accordingly.
To check the accuracy of the oscillator you must have a cali-
brated reference signal that is at least five times more stable
than the oscillator that you are testing. See Table 2-7 and the
list of test equipment on page 2-2. If you use a non-10 MHz
reference, you can use the mathematics in the timer/counter to
multiply the reading.
– Recall the DEFAULT settings. See page 2-2
– Connect the reference to input A
– Check the readout against the accuracy requirements of
your application.
n
Acceptance Test
Oscillator
Standard
(PM6690/_1_)
OCXO
(PM6690/_5_)
OCXO
(PM6690/_6_)
Table 2-7
Table 2-7 can serve as an acceptance test and gives a worst
case figure after 30 minutes warm-up time. All deviations that
can occur in a year are added together.
Resolution Test
– Connect the pulse generator to a power splitter.
– Connect one side of the power splitter to Input A on the
counter using a coaxial cable.
– Connect the other side of the power splitter to Input B
on the counter.
Settings for the pulse generator:
– Amplitude = 2 V
– Period = approx. 1 ms
– Duration = approx. 50 ns
– Rise time = 2 ns
Restore the timer/counter's default settings and make the fol-
lowing changes:
– Function =
– Press STAT/PLOT key to the right of the display.
– Settings for
W input impedance
50
ual trigger level
MAN
Performance Check, Short Form Specification Test 2-5
Frequency Readout
10.00000000 MHz ± 150 Hz
10.00000000 MHz ± 1 Hz
10.00000000 MHz ± 0.25 Hz
Acceptance test for oscillators.
, (high level +2V and low level 0 V)
PP
Time A-B
and :
INPUT A INPUT B
Suitable P/F
Reference
908
909
909