–
Press
INPUT A and select MANual trigger level and 50 W
input impedance.
–
Connect the LF synthesizer to Input A. Use the follow
-
ing settings (into 50 W):
Sine, 10 kHz, 0.9 V
PP
, and +0.50 V
DC
.
–
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
EXIT/OK. Check the trigger
indicator according to Table 2-4.
–
Press the
Trig key and enter –1 V via the keyboard
by pressing the
± key, then verify by pressing
EXIT/OK. Check the trigger indicator according to
Table 2-4.
–
Press the
Trig key and enter 0 via the keyboard, then
verify by pressing
EXIT/OK. Check the trigger indica
-
tor according to Table 2-4.
–
Apply the signal to Input B instead.
–
Press
MEAS FUNC ® Freq ® Freq (A) ® B
–
Press
INPUT B and select MANual trigger level and
50 W input impedance..
–
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 DC and 50 W.
– Press
EXIT/OK.
– Check the V
max
and V
min
voltage levels on the display
according to the first row in Table 2-6.
– Perform the rest of the settings in sequence, and read the
corresponding V
max
and V
min
values. Remember that all
these values are approximate and serve only as indica
-
tors of state changes.
–
Connect the generator to Input B.
–
Press
MEAS FUNC ® Freq ® Freq (A) ® B
–
Press
INPUT B and select DC and 50 W.
–
Press
EXIT/OK.
–
Check the V
max
and V
min
voltage levels on the display
according to the first row in Table 2-6.
–
Perform the rest of the settings in sequence, and read the
corresponding V
max
and V
min
values.
Reference Oscillators
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 mathemati cs 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
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
PP
, (high level +2V and low level 0 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 =
Time A-B
–
Press STAT/PLOT key to the right of the display.
–
Settings for
INPUT A and INPUT B:
50 W input impedance
MANual trigger level
Performance Check, Short Form Specification Test 2-5
Settings V
max
V
min
Pass/Fail
Input A Input B
INPUT A, DC, 50 W
+950 mV
+50 mV
AC
+450 mV
-450 mV
10X
+0.45 V
-0.45 V
1MW
>+0.45 V
<-0.45 V
Table 2-6 Input controls check.
Oscillator Frequency Readout Suitable
Reference
P/F
Standard
(PM6690/_1_)
10.00000000 MHz ± 150 Hz
908
OCXO
(PM6690/_5_)
10.00000000 MHz ± 1Hz
909
OCXO
(PM6690/_6_)
10.00000000 MHz ± 0.25 Hz
909
Table 2-7 Acceptance test for oscillators.
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