MICROWAVE RADAR TESTING 



479 



employed. The amplitude of pulse applied to the magnetron is thousands 

 of volts. To derive a voltage suitable for application to the oscilloscope, a 

 voltage divider of the condenser type is used (TS-89/AP). Suitable video 

 terminations, dividers, and loads, sometimes of high voltage and power 

 capacity, are required to obtain proper test conditions and provide con- 

 venient test points (TS-98/AP, TS-390/TPM-4, TS-90/AP, TS-234/UP). 

 Originally a high-impedance connection to the oscilloscope was effected by 

 a single-stage amplifier unit (BC1167A), but a simple divider type of probe 

 was later found more satisfactory for this purpose. 



• NAL 

 'UT 



COUPLING 

 AMPLIFIER 



DELAY 

 NETWORK 



SIGNAL 

 AMPLIFIER 



>> 



BRIGHTNESS 

 D VV\ 1 



RNAL 

 NC 



SYNC 

 AMPLIFIER 



START- STOP 

 , 1 SWEEP GENERATOR 



n -A-i-A. 



SAWTOOTH 

 SWEEP GENERATOR 



SWEEP 

 AMPLIFIER 



Fig. 26— Block diagram of TS-34/AP and TS-34A/AP oscilloscopes. 



Range Calibration 



Types of timing circuits used for radar range determination include (a) 

 multi-vibrators, (b) coil and condenser oscillators (generally without but 

 sometimes with temperature control) and occasionally (c) quartz crystal 

 oscillators. The first two depend for their accuracy on condensers, re- 

 sistances, coils and other elements which are subject to error due to aging, 

 temperature, humidity, mechanical damage and the like. Nor is the quartz 

 cr}-stal oscillator wholly immune to error. Consequently, portable range 

 calibrators are required for field maintenance. 



