Fluke 5820A, Service Manual

Page: 71 / 158

Calibration and Verification
Verification
3
3-33
Table 3-16. Edge Rise Time Verification
Calibrator Mainframe Output
DSO
Vertical
Axis
A B
Voltage Frequency
(mV/div)
11801
Reading
Corrected
Reading Tolerance
250 mV 1 kHz 20.0 < 300 ps
250 mV 1 MHz 20.0 < 300 ps
250 mV 10 MHz 20.0 < 350 ps
500 mV 1 kHz 50.0 < 300 ps
500 mV 1 MHz 50.0 < 300 ps
500 mV 10 MHz 50.0 < 350 ps
1 V 1 kHz 100.0 < 300 ps
1 V 1 MHz 100.0 < 300 ps
1 V 10 MHz 100.0 < 350 ps
2.5 V 1 kHz 200.0 < 300 ps
2.5 V 1 MHz 200.0 < 300 ps
2.5 V 10 MHz 200.0 < 350 ps
3-40. Edge Aberrations
The following equipment is needed for this procedure:
•
High Frequency Digital Storage Oscilloscope: Tektronix 11801 with Tektronix SD-
22/26 sampling head
•
N to BNC output cables provided with the Scope Calibrator (2)
Before you begin this procedure, verify that the Scope Calibrator is in the edge mode
(the Edge menu is displayed), program it to output 1 V p-p @ 1 MHz, and press the soft
key under TRIG to select the TRIG/1 External Trigger output. Press
to activate the
output and trigger.
Set the DSO vertical to 10 mV/div and horizontal to 10 ns/div. Next, set the signal edge
against the left side of the DSO display. Mentally note the signal amplitude 90 ns from
the edge; use this point as the reference level. It maybe helpful to set the DSO to average
4 per reading. Now set the DSO to 1 ns/div and look at the first 10 ns of the edge signal
with the rising edge at the left edge of the DSO display.
With the vertical setting, each line on the DSO represents a 1% (i.e. 10 mV) of
aberration. Determine that the Scope Calibrator falls within the typical specifications
shown in Table 3-17. For time greater than 10 ns, set the DSO to 10 ns/div. Verify the
aberrations are within specification.
Table 3-17. Edge Aberrations
Time from 50% of Rising Edge Typical Edge Aberrations
0 - 2 ns < 32 mV (3.2%)
2 - 5 ns < 22 mV (2.2%)
5 - 30 ns < 12 mV (1.2%)
> 30 ns < 7 mV (0.7%)