170 



BELL SYSTEM TECHNICAL JOURNAL 



Again dividing by jSa to obtain the frequency as a ratio of driven to undriven 

 crystal frequency, we have 



/3a Pi 



&l 



^l 



f. - 



/(SJ 



4P4 



m 



4P4 



(12.12) 



(12.13) 



.94 



.96 



MEASURED FREQUENCY 



COMPUTED DRIVEN 



FREQUENCY 



1.06 



Fig. 12.6 — The oscillating frequency as a function of the plate circuit frequency for the 

 crystal connected grid to plate (G-P) and grid to cathode (G-C) 



The frequency change as a function of plate circuit tuning was determined 

 graphically in the manner described in section (12.11) and the curves are 

 shown in Fig. 12.6 as the G-C curves. 



12.13 Resistance Load Circuit 



This is a special case of Plate-Grid connection of the crystal described in 

 section (12.11) in which the plate circuit consists of a capacitance and re- 

 sistance in parallel. This is a very common Pierce type of oscillator circuit 

 and has the advantage that no tuning adjustment is necessary when using 

 crystals of different frequencies. 



