HP 54710A User's Reference Manual page 225

Measurements
Time-interval measurements
Table 13-3 Rise Time Errors for Plug-In and Probe Combinations
Plug-In and Probe
HP 54711A
HP 54711A and 54006A
HP 54711A and 54701A
HP 54712A
HP 7412A and 54006A
HP 54712A and 54701A
HP 54713A
HP 54713A and 54701A
HP 54713A and 10430A
HP 54721A
HP 54721A and 54006A
HP 54721A and 54701A
You can apply the concepts of rise time measurement to measuring the
interval between two identical edges at different levels. The error in
measuring the interval from the 10 percent level on one edge to the 90
percent level on some later edge is the same as the error in measuring rise
time.
13–40
Actual rise time
500 ps 1 ns 2 ns
10.4% 2.7% 0.7%
10.4% 2.7% 0.7%
13.8% 3.6% 0.9%
18.5% 4.9% 1.3%
18.5% 4.9% 1.3%
22% 5.9% 1.5%
72% 22% 5.9%
72% 22% 5.9%
72% 22% 5.9%
18.5% 4.9% 1.3%
18.5% 4.9% 1.3%
22% 5.9% 1.5%
3 ns
0.3%
0.3%
0.4%
0.6%
0.6%
0.7%
2.7%
2.7%
2.7%
0.6%
0.6%
0.7%