Time Marker Verification - Fluke 5520A Service Manual

6-132. Time Marker Verification

This procedure uses the following equipment:
PM 6680 Frequency Counter with a prescaler for the Channel C input
(Option PM 9621, PM 9624, or PM 9625) and ovenized timebase (Option PM 9690
or PM 9691)
BNC(f) to Type N(m) adapter
BNC cable supplied with the SC300
Refer to Figure 6-21 for the proper setup connections. Set the PM 6680's FUNCTION to
measure frequency with auto trigger, measurement time set to 1 second or longer, and
50 impedance.
Set the Calibrator Mainframe to SCOPE mode, with the Marker menu on the display.
Press on the Calibrator Mainframe to activate the output. Then follow these steps
to for each period listed in Table 6-57.
1. Program the Calibrator Mainframe to the output as listed in Table 6-57.
2. Using the BNC cable, connect the SCOPE connector on the Calibrator Mainframe to
the PM 6680 at the channel indicated in Table 6-57. You will need the BNC-N
adapter for the connection to Channel C.
3. Set the filter on the PM 6680 as indicated in the table. Allow the PM 6680 reading to
stabilize, then record the PM 6680 reading for each frequency listed for the
Calibrator Mainframe.
4. Invert the PM 6680's frequency reading to derive the period. For example, a reading
of 1.000006345 kHz has a period of:
1/1.000006345 kHz = 0.999993655 ms.
Record the period in the table and compare to the tolerance column.
Calibrator PM 6680 Settings
Mainframe
Channel
Period
4.979 s A
2.002 s A
0.999 s A
500 ms A
200 ms A
100 ms A
50.0 ms A
20.0 ms A
10.0 ms A
5.00 ms A
2.00 ms A
1.00 ms A
500 s A
200 s A
Table 6-57. Time Marker Verification
Impedance Filter
50 On
50 On
50 On
50 On
50 On
50 Off
50 Off
50 Off
50 Off
50 Off
50 Off
50 Off
50 Off
50 Off
PM 6680
1/(PM 6680
Reading)
Reading
(Period)
(Frequency)
SC300 Option 6
Verification
Tolerance
25.12 ms
4.050 ms
1.0300 ms
262.500 s
45.000 s
12.500 s
3.750 s
900.00 ns
350.00 ns
150.00 ns
54.00 ns
26.00 ns
12.750 ns
5.040 ns
6-103