2-43
Figure 2-30A.—Fixed target cancellation.
Figure 2-30B.—Fixed target cancellation.
In figure 2-31, 30-megahertz signals from the signal mixer are applied to the 30-megahertz amplifier.
The signals are then amplified, limited, and fed to the phase detector. Another 30-megahertz signal,
obtained from the coherent oscillator (coho) mixer, is applied as a lock pulse to the coho. The coho lock
pulse is originated by the transmitted pulse. It is used to synchronize the coho to a fixed phase
relationship with the transmitted frequency at each transmitted pulse. The 30-megahertz, cw reference
signal output of the coho is applied, together with the 30-megahertz echo signal, to the phase detector.
