Fluke 5820A, Service Manual

Page: 93 / 158

Calibration and Verification
Verification
3
3-55
the N to BNC cable to one BNC(f) to SMA(m) adapter then to the DSO’s channel 1
sampling head through the 3 dB attenuator.
Using the second N to BNC cable, connect to the Calibrator Mainframe’s EXT TRIG
(channel 5) connector. Connect the BNC end of the cable to a BNC(f) to SMA(m)
adapter. Next, connect the adapter to one end of the SMA T connector. Connect the T
connector to the 3 dB attenuator and attached the attenuator to the DSO's channel 2
sampling head. The other end of the T connector should be connected through a 0.5-M
cable to the trigger input of the DSO.
3-55. Calibration
On the Scope Calibrator keypad, select SETUP. On the display select the Cal soft key.
Next select Cal 58XXA soft key. For the next soft key selections, press Options followed
by Next until you see the message, “Adjust Trigger Skew to 0.0”. Follow the front panel
skew calibration procedure until you see the message, “Connect 40 ohm Resistor”. At
this point select Options and then Save the calibration constants.
3-56. Verification
On the Calibrator keypad, select
5
. On the display, press the soft key under Pulse.
Press the soft key under TRIG to select the TRIG/1 External Trigger output. Program the
Calibrator Mainframe to output 1 ns pulse width and 3
µ
s period at 1.5 V with no skew
(i.e. the rising trigger edge against the rising pulse). Press on the Calibrator to
activate the output. Press the soft key under SKEW.
Auto set the DSO. Then set the DSO to these starting values:
Main Time Base position (initial) 2 ns/div
Vertical scale channel 1 (Pulse) 200 mV/div
Vertical scale channel 2 (Ext Trig) 100 mV/div
Trigger source = ext; level = 200 mV; ext atten = x1; slope = +;
mode = auto
Measurement Function none
1. Set skew = 0.0 ns. Verify the skew between the 30% level of the trigger and pulse
edge is less than 500 ps.
2. Use the values in the Table 3-27 to verify the skew specification. Change the
horizontal scale of the DSO as needed. Record the skew measurement made and
compare to the tolerance column of Table 3-27. Continue through the values in the
table recording results.
Table 3-27. Pulse Skew
Pulse
Amp.
Function Measurement Skew Width Period
Measured
Value Deviation Spec (s)
1.5 V pulse skew 0.0E-09 1.0E-09 3.0E-06 500.0E-12
1.5 V pulse skew -10.0E-09 1.0E-09 3.0E-06 500.0E-12
1.5 V pulse skew -5.00E-09 1.0E-09 3.0E-06 500.0E-12
1.5 V pulse skew 15.0E-09 1.0E-09 3.0E-06 500.0E-12
1.5 V pulse skew 30.0E-09 1.0E-09 3.0E-06 500.0E-12