450 



REGULATORY CIRCUITS 



As in all feedback control systems, the error signal is used to position the 

 antenna in a direction which will decrease the error. Generally, however, 

 the control system characteristics shown in Fig. 8-31 do not exist naturally, 

 and it is necessary to provide some form of compensation. On small, 

 low-power systems this compensation can be provided mechanically by 

 adding extra inertia to the antenna inertia with fluid coupling; but with 

 large antennas where space is limited and the power is relatively high, 

 it is more practical to provide electrical compensation in the form of RC 

 networks as shown in Fig. 8-35. Design formulae are given to illustrate how 

 the network parameters are related to the corner frequencies. Generally, 

 the corner frequencies are chosen so that, in combination with the corner 

 frequencies of other equipment in the loop, the desired overall characteristic 

 shown in Fig. 8-31 is obtained. This is illustrated in Fig. 8-36. It should be 

 noted that networks A and especially B of Fig. 8-35 would be used in series 

 with the low-power circuits in the forward path of the search loop, and that 



1.0 



Fig. 8-36 Method of Determining Control-Loop Compensating Function. 



