Bird Technologies 8890-400 Series - Manuale (Pagina 16)

Coupling
Circuit
The coupling circuit which samples the travelling waves is
in the plug-in element. Energy will be produced in the cou-
pling circuit of the element by both mutual inductance and
capacitance from the travelling RF waves of the line section.
The inductive currents will flow according to the direction of
the travelling waves producing them. Refer to figure 3 for
the schematic diagram of an element.
The capacitive position of these currents are naturally inde-
pendent of the direction of the travelling waves. Therefore,
it is apparent that the inductive portion of the current pro-
duced from the waves of one direction will add in phase to
the capacitive portion of the current, and those of the oppo-
site direction will subtract in phase. The additive direction
is the forward or arrow direction of the element.
6
Bird Model 8890-400 Series Termaline Wattmeter
Stop Pin
Contact
Figure 2
Element
Contact &
Stop-Pin
RF Coaxial Line
RF Power
Input/Output RF Power
Output/Input
Directional Coupling
Detector Element
Diode
Meter
Bypass Capacitor
DC Contact DC Connector
Figure 3
Schematic
Diagram