COIL PULSERS FOR RADAR 



613 



with added reactors of small size to provide harmonic resonances needed 

 to shape the discharge pulse. These help to bring up the third and fifth, 

 and in some cases higher harmonics. 



Results after shaping are shown in Fig. 4 for two extremes of pulse width. 

 The shorter pulse, roughly a quarter microsecond in average duration, 



Fig. 4 — Shaped magnetron current i)ulscs, together with the radio l"re(iuency si)ectro- 

 grams corresponding. Pulse at u])per left indicates ])resence of high harmonics; pulse at 

 upper right shows strong fifth harmonic and little at higher harmonics. The band width 

 of the main energy lobe, and the dispersion of energy outside that band in both cases indi- 

 cate negligibly srnall effect attriliutable to fretjuency modulation. 



evidences the presence of fairly high harmonics. The wider pulse, roughly 

 one and a quarter microseconds in average duration, has a strong fifth 

 harmonic and some even harmonics as well.^ Below each pulse is shown a 

 spectrogram of the corresponding magnetron high-freqtiency output, which 



5 Magnetron currents are shown rather than voltages, since current is a far more 

 sensitive indicator of performance. 



