THE RADAR RECEIVER 



799 



is provided whose rotation between the stator elements affects each quad- 

 rant stator capacitance in a like manner. As illustrated the resultant out- 

 put voltage which appears from the ring stator to ground has a phase shift 

 relative to any applied wave which varies linearly with angular displace- 

 ment of the condenser shaft. 



The function of the following amplifier shown in Fig. 64 is to provide a 

 high-impedance termination for the phase-shifting condenser, and to pro- 

 vide increased amplitude of the timing wave. The pulse generator which 

 follows limits or clips the applied timing wave, and differentiates the re- 



!B+ 



FROM 



START- STOP 



CIRCUIT 



TIMING- WAVE 

 GENERATOR PHASE- SHIFTERS 



Fig. 65. — Timing wave generator circuit of phase shifter t}-pe range unit. 



sultant wave form. The output here consists of trains of alternate positive 

 and negative timing pulses. 



The pulse selector component shown in Fig. 64 enables obtaining delay 

 intervals greater than 12.2 microseconds the value associated with 360° 

 phase shift of the timing wave. An increasing exponential saw-toothed 

 wave form is generated starting at zero time reference by an RC circuit 

 having a time constant of the order of 800 microseconds. The timing pulses 

 are applied additively with this exponential to the grid of a vacuum tube 

 operating below cutoff, its exact value of bias being determined by the 

 setting of a potentiometer control. At the time that the grid signal ampli- 

 tude exceeds this critical cut-off bias value, this tube conducts abruptly as 



