Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

502 FREQUENCY MODULATION, Volume 1CARRIER AND SIDE-FREQUENCY RELATIONS WITHMULTI-TONE FREQUENCY OR PHASEMODULATIONSByMurray G.CrosbyRCA Communications, Inc., Riverliead, L. I., N. Y.SummaryThe equation for the carrier and side frequencies of a frequency orphase-modulated wave is resolved for the case of two applied modulatingtones. It is shown that when more than one modulating tone is applied, theamplitude of the carrier is proportional to the product of the zero-orderBessel Functions of all the modulation indexes involved. The amplitudesof the side frequencies are proportional to the products of Bessel Functionsequal in number to the number of tones applied and having orders respectivelyequal to the orders of the frequencies involved in the sidefrequency. Beat side frequencies are produced which have higher-orderamplitude and do not appreciably widen the band width occupied by frequencymodulation.(4 pages)* Decimal Classification: R630.1.f RCA REVIEW, July, 1938.SOME RECENT DEVELOPMENTS IN RECORDREPRODUCING SYSTEMS*fByG. L. BEERSt AND C. M. SlNNETT#RCA Manufacturing Co., Inc., Camden, N. J.SummarySeveral factors of importance in obtaining satisfactory reproductionof sound from lateral-cut phonograph records are considered. An experimentalrecord reproducing system employing the principles of frequencymodulation is described and data are supplied on the measured and calculatedperformance characteristics of the system. Curves are includedshowing the vertical force required for satisfactory tracking with theexperimental frequency-modulation pickup as compared with other pickupsof conventional design.(9 pages; 18 figures; Appendix)* Decimal Classification : R681.843.f Proc. I.R.E., April, 1943.J Now Asst. Director of Engineering in Charge of Advanced Development,RCA Victor Division, Camden, N. J.# Now with the Home Instrument Department, RCA Victor Division,Camden, N. J.