1120 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1956 



taken from the signal oscillator to provide monitoring and wavemeter 

 indication. The remaining power, after suitable padding, is fed into a 

 3-db directional coupler or hj^brid junction 2. This junction is employed 

 as a waveguide bridge so that, when arms A and B are properly termi- ' 

 nated, no power flows in receiving arm C. Any reflection in line A will, 



WAVE 

 METER 







MONITOR 



SIGNAL 

 OSCILLATOR 



X 



•-10DB 



, Q 



oDB v_y 



I 



^4- 



2>/ 



^3DB COUPLER WAVEGUIDE 



/-^{HYBRID JUNCTION) SWITCH 



/ y^ ROUND 



TUNER TAPER ^^ <• WAVEGUIDE 



LINE 



X TE 





TEo, TEo, 



Fig. 3 — Schematic of measuring equipment. 



ADJUSTING 

 KNOB 



-RG 98/u 



Fig. 4 — Structure of impedance matching tuner. 



