2-26
Figure 2-18.—Series-connected duplexer during transmission.
During reception, neither spark gap is fired, as shown in figure 2-19. The atr acts as a half-wave stub
terminated in an open. This open is reflected as a short-circuit at the T-junction three-quarters of a
wavelength away. Consequently, the received signal sees a low impedance path to the receiver, and none
of the received signal is lost in the transmitting circuit.
Figure 2-19.—Series-connected duplexer during reception.
DUPLEXER TYPES
Duplexers are constructed in many forms, such as RESONANT-CAVITY COAXIAL SYSTEMS,
WAVEGUIDE SYSTEMS, and HYBRID RINGS. Since waveguide and hybrid-ring duplexers are most
common in radar systems, those will be discussed in this section.
