MICROWA VE REPEA TER RESEA RCH 233 



match requirements. The research on these major factors and many 

 subsidiary details resulted in a converter which had an output of 6 miUi- 

 watts with less than 0.1 db compression, good input and output match, a 

 flat amphtude response over more than 10 megacycles, and a conversion 

 loss of about 11 db. 



Fig. V-12. — Unbalanced to balanced coaxial transformer for feeding the 65 mc signal 

 to the transmitting converter. 



This converter, or transmitting modulator, had the 1N28 crj^stals mounted 

 in the conjugate branches of a waveguide hybrid junction, as shown in Fig. 

 V-11. Adjustable coaxial sleeves surrounded the crystal cartridges in or- 

 der to effect an impedance match to the waveguide, and tuning studs were 

 provided for trimming adjustments. The beating oscillator was injected 

 into the hybrid junction through a broad-band coaxial-to-waveguide trans- 

 ducer in the upper branch of the hybrid junction, and the sidebands appeared 

 in the conjugate waveguide branch. The 65-megacycle signal was fed onto 

 the crystals in push-pull through the unbalanced to balanced coaxial trans- 

 former shown in Fig. V-12. Blocking condensers enabled the crystal cur- 

 rents to be monitored separately and RF filters kept the 4000-megacycle 



