Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

440 FREQUENCY MODULATION, Volume I5, the calculated amplitude—instantaneous-input-frequency response,agrees very closely with (b) of Figure 2, the experimental amplitude—instantaneous-input-frequency response. The reader may be interestedin comparing the results of the calculation with the resultsobtained by Roder on a very similar problem, which he solved by theaid of a differential analyzer. His response curve was plotted as afunction of time. 7XVI (t) . For each of the work sheets prepared for different assignedvalues of vt, plot on the response graphs.Q = the response at 2-n- — vtR = the response at vtS = the response at -n-+ vtT = the response at it — vt.The magnitudes of Q, R, S, and T for each work sheet give four pointson the desired amplitude—time response curve. The phases of Q, R,S, and T give four points on the desired phase-shift—time-responsecurve.AppendixIf a steady-state driving voltage e' at is applied to the input terminalsof a linear network, it can be shown that the steady-state solutionfor the voltage at the output terminals 8 is of the form -R(m)£ j[o)H-0] # r ( ra ) is the ratio of the peak amplitudes of the output andinput voltages, and 6(a>) is the phase difference. Abbreviating e^ (as E lv+ and R(a>) e K*+ei°>n as E mt +, it follows thatE oat +=E ln+RM *M«K (34)Furthermore, if a steady-state driving voltage £-*>* is applied to theinput terminals of the same linear network, itcan be shown that thevoltage at the output terminals is of the form R (-whereR and 6 are equal to R and of (34). Setting e~> at as E in~ andRM £ -;[«*+«.(35)7Hans Roder, "Effects of Tuned Circuits upon a Frequency-modulatedSignal," Proc. I.R.E., vol. 25, pp. 1617-1648; December, 1937.«H. Pender and S. Warren, ELECTRIC CIRCUITS AND FIELDS,McGraw-Hill Book Company, New York, N. Y., 1943, pp. 161-163.