User's Manual

The output directional coupler is a discrete component with a nominal coupling of -20 dB and a minimum
directivity of 20dB. The coupler is used to sample the transmitted RF signal and detect any reflected
signals due to load mismatches. Both the forward and reflected signals are further attenuated by 10dB
attenuators and are converted to video signals by differential diode detectors before being passed to the
Modulator CCA. Both the forward and reflected detectors have 25dB of linearity. The coupler/detector
section of this CCA is placed in a separate cavity for shielding purposes.
Figure 1-7 Low Power DME Amplifier Block Diagram