Atek HP 8753D, Руководство пользователя, Страница: 333 / 677

Electrical Oset
Some standards have reference planes that are electrically oset from the mating plane of the
test port. These devices will show a phase shift with respect to frequency . T able 6-3 shows
which reference devices exhibit an electrical oset phase shift. The amount of phase shift can
be calculated with the formula:
= (360 x f x l)/c where:
f = frequency
l = electrical length of the oset
c = speed of light (3 x 10
8
meters/second)
Fringe Capacitance
All open circuit terminations exhibit a phase shift over frequency due to fringe capacitance .
Oset open circuits have increased phase shift because the oset acts as a small length of
transmission line . Refer to T able 6-3.
T able 6-3. Calibration Standard Types and Expected Phase Shift
T est P ort
Connector Type
Standard Type Expected Phase Shift
7-mm Short 180
Type-N male
3.5-mm male Oset Short
180 +
(360 2 f 2 l )
c
3.5-mm female
2.4-mm male
2.4-mm female
Type-N female
75 Type-N female
7-mm Open 0 +
capacitance
Type N-male
3.5-mm male Oset Open
0 +
capacitance
+
(360 2 f 2 l )
c
3.5-mm female
2.4-mm male
2.4-mm female
Type N-female
O pen 0 +
capacitance
+
(360 2 f 2 l )
c
75 Type-N female
Application and Operation Concepts 6-67