board. This is not considered serious, since on the final system the amplitude 

 would remain fixed after the optimum value has been determined. Another effect 

 is observed if all of the phases are advanced by the same value: since the num- 

 ber of phase errors between bits is not the same for all bits, changes in the radia- 

 tion pattern occur as the beam is scanned through 360°. This effect will also be 

 minimized if a phase-trimming scheme is used in the system. As in the case of 

 the matrix previously discussed, the phasor board is a discrete phase-step device 

 and will be subject to changes in beam-pointing direction as the frequency is 

 changed. This is not a serious problem for the circular array, but for elevation 

 scanning it would be a factor to be investigated. 



0° 

 ANGLE (°) 



180° 



Figure 49. CARAMBA IT azimuth difference pattern obtained by advancing phase-control 

 switches 180°, 0.95 f a . 



14 



