10-4] 



SYSTEM REQUIREMENTS FOR RADAR ANTENNAS 



519 



The tracking function stands in need of more analysis, however. For a 

 conical scanning radar, the tracking error signal is an amplitude modulation 



_ -8 



-16 



4/UJ \ \\(h 



-1.6 



■1.2 -0.8 -0.4 0.4 0.8 1.2 



(a) TYPICAL CROSSOVER PAHERN 



1.6 



-1.2 



-0.8 -0.4 0.4 0.8 



(b) FUNDAMENTAL MODULATION 



1.2 



1.6 



-1.6 



■1.2 -0.8 -0.4 0.4 0.8 



(c) 2d HARMONIC MODULATION 



Fig. 10-4 Tracking Error Signal as Derived from a Conical Scan Radar Antenna: 

 (a) Typical Pattern with the Beam Offset to a l|-db Crossover, (b) The Per Cent 

 Fundamental Modulation or Error Signal in Conical Scan as a Function of Target 

 Error and Beam Offset, (c) The Per Cent Second Harmonic Signal Which Is Not 

 Useful as Tracking Information but Which Can Cause System Problems. 



