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wanted sideband back into the modulator in proper phase, thereby making 

 the length of the line going to the RF amplifier much less critical. The 

 proper phase of reflection was obtained by adjusting the length of the 

 waveguide between the modulator and the reflecting filter. The IF imped- 

 ance of the crystals could thus be varied so as to obtain an impedance 

 match between the IF amplifier and the crystals. 



Fig. V-11. — Exj)erimental model of transmitting converter. 



An investigation of the power capacity of various types of standard and 

 special silicon crystals indicated that one similar to the 1N28 crystal was 

 the best available for this service, and life tests were made to check the sta- 

 bility of the crystal under high level conditions. Special IF input and 

 crystal-to-waveguide matching circuits were developed to meet the stringent 



i 



