MICROWAVE REPEATER RESEARCH 



225 



oscillator second harmonic and the signal) which in turn afifects the converter 

 output impedance and hence the match between the rectifiers and the IF 

 transformers. Failure to obtain a proper match results in non-uniform 

 transmission over the channel band. 



In addition, to maintain uniform conversion efficiency over a wide band, 

 it is necessary to control the impedance encountered by frequencies near the 

 beating oscillator second harmonic. This is done by means of the harmonic 



TRANSFORMER 

 TUNING \ 

 CAPACITOR 



I-F 

 TRANSFORMER 



BEATING- 

 OSCILLATOR 

 NPUT 



Fig. V-4. — Receiving converter with input filter. 



filters shown which reflect these frequencies from a point close to the recti- 

 fier. Since the point of reflection is close, there is little opportunity for the 

 phase of the reflection, and hence the conversion loss, to vary over the band 

 of frequencies to be converted. 



The converter in Fig. V-4 was designed to provide as good a termination 

 as possible to the incoming waveguide over the band of channel frequencies 

 so that a minimum of additional adjustment would be required to match 

 the guide accurately at any particular channel frequency. This additional 



