KEGENERATION OF BINARY MICROWAVE PULSES 



81 



Fig. 14 — The regeneration of pulses in the presence of interference occurring 

 at each repeater. A — Original signal with added moduhited carrier interference. 

 B — Input to regenerator, 24th trip, niochilatod carrier interference. C — Output 

 of regenerator, 24th trip, modulated carrier interference. 



produced a considerable broadening of the oscilloscope trace. Fig. 13B 

 shows the same pulse groups with no added noise. These photographs are 

 included to give some idea as to how bad the noise was at the l;)reaking 

 point of the system. Of course maximum noise peaks occur rather infre- 

 quently and do not show on the photograph. At the output of the re- 

 generator effects due to noise were barely discernible. This output looked 

 so much like that shown at Fig. 14C that no separate photograph is 

 shown for it. 



Figs. 14A, 14B and 14C show the effects of a different type of inter- 

 ference upon the system. This disturbance was produced by adding into 

 the system a carrier of exactly the same frequency as the signal carrier 

 (4 kmc) but modulated by a 14-mc wave, a frequency in the same order 

 as the pulse rate. Here again the level of the interference was adjusted 

 to be just below the l)reaking point of the system. A comparison between 

 Figs. 14B and 14C gives convincing evidence that the regenerator has 

 substantially restored the waveform. 



For the case of the interfering signal a ratio of signal to interference 

 of 10 db on a peak-to-peak basis was measured when the interference 

 was just below the breaking point of the system. This, of course, is 4 db 

 above the theoretical value for a perfect regenerator. For the case of 



