Fluke PM6690 - Trigger Level Check; Reference Oscillators

Trigger Level Check
–
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.
–
Check the first V
max
and V
min
voltage lev
-
els on the display according to Table 7-5.
–
Perform the rest of the settings in se
-
quence, and read the corresponding V
max
and V
min
values. Remember that these val
-
ues are approximate and serve only as in
-
dicators 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
–
Perform the settings and check the Vmax
and Vmin values for Input B according to
Table 7-5.
Reference Oscillators
X-tal oscillators are affected by a number of
external conditions 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 decide the limits depending on
his application, and recalibrate the oscillator
accordingly.
To check the accuracy of the oscillator you
must have a calibrated reference signal that is
at least five times more stable than the oscilla
-
tor that you are testing. See Table 7-6 and the
list of test equipment on page 7-2. If you use a
non-10 MHz reference, you can use the math
-
ematics in the timer/counter to multiply the
reading.
–
Recall the DEFAULT settings.
–
Connect the reference to input A
–
Check the readout against the accuracy re
-
quirements of your application.
n
Acceptance Test
Table 7-6 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.
Performance Check
7-8 Short Form Specification Test
Oscillator Frequency Readout Suitable Reference P/F
PM6690/_1_ (Standard)
10.00000000 MHz ± 150 Hz
908
PM6690/_5_(OCXO)
10.00000000 MHz ± 1Hz
909
PM6690/_6_(OCXO)
10.00000000 MHz ± 0.25 Hz
909
Table 7-6 Acceptance test for oscillators.