Porch; Bullet On The Porch - Fluke 5820A Service Manual

5820A
Service Manual
9. Adjust R175 so that a porch-waveform can be observed (refer to Figure 5-3).
10. Adjust the oscilloscope vertical setup to be 5 mV/Div.
11. Adjust R188 to make the bullet waveform shown in Figure 5-4. Its amplitude should
12. Adjust R175 to raise the porch level to the height at which fast edge is stable (refer
13. Use a cursor on the scope to mark this porch level (Level I).
14. By adjusting R175, continue to raise the porch level to the height at which the fast
15. Use a cursor on the scope to mark this porch level (Level II). A typical voltage
5-8
not be less than 7 mV.
Figure 5-4. Bullet on the Porch
to figure 5-5).
edge waveform is unstable.
difference between Level I and Level II is 20 mV. (Refer to Figure 5-6).
Figure 5-3. Porch
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