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BELL SYSTEM TECHNICAL JOURNAL 



on the Smith Chart) as well as on the length of the line. Mm changes most 

 rapidly with frequency in the very high admittance region. 



As a simple example of the effect of a short mismatched line on electronic 

 tuning between half power points, consider the case of a reflex oscillator 

 with a lossless resonator so coupled to the line that the external Q is 100 

 and the electronic conductance is 3 in terms of the line admittance. Sup- 

 pose we couple to this a coaxial line 5 wavelengths long with a standing wave 

 ratio cr = 2, vary the phase, and compute the electronic tuning for various 



0.04 0.06 008 010 0.12 QW ai6 0.18 0.20 022 Q24 0.26 

 VOLTAGE STANDING -WAVE RATIO PHASE IN CYCLES PER SECOND 



Fig. 50. — The normalized load conductance, the characteristic admittance of the resona- 

 tor and the normalized electronic tuning range to half power plotted vs standing wave 

 ratio phase for a particular case involving a short misterminated line. The electronic 

 tuning for a matched line is shown as a heav\' horizontal line in the |ilot of (Aw/coo)! . 



phases. We can do this by obtaining the conductance and Ml from Fig. 

 49 and using Fig. 15 to btain (Aw/wo)j . In Fig. 50, the parameters 

 GlIJc (the total characteristic admittance including the effect of the line), 

 A'', and, finally, (Aaj/wo)j have been plotted vs standing wave phase in 

 cycles. (Ac<j/ajo)j for a matched load is also shown. This example is of 

 course not tyi:)ical for all reflex oscillators: in some cases the electronic tuning 

 might be reduced or oscillation might stop entirely for the standing wave 

 phases which produce high conductance. 



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