Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

SUMMARIES— MISCELLANEOUS 503FREQUENCY MODULATION OF RESISTANCE-CAPACITANCE OSCILLATORS*!ByMaueice AktztResearch Department, RCA Laboratories Division,Princeton, N. J.SummaryA method is described for direct-frequency modulation of a resistancecapacitanceoscillator which is simpler and more stable then the beatoscillators formerly used. Spurious amplitude modulation is reduced to anegligible value without the use of limiters and without introducing appreciableharmonics in the output wave. Balanced control tubes preventtransients or signal frequencies from appearing in the output. Curvesare given which provide an easy method of choosing the network andconstants for any desired condition. The device is especially suited tofacsimile transmission by sub-carrier frequency modulation.(6 pages; 9 figures)* Decimal Classification : R148.5.f Proc. I.R.E., July, 1944.AN F-M CALIBRATOR FOR DISCRECORDING HEADS*!ByH. E. KoysEngineering Products Department, RCA Victor Division,Camden, N. J,SummarySince the beginning of disc recording, a device has been needed whichwould permit the calibration of a recording head under actual cuttingconditions. Such a devise is described in this paper. First, however, variousformer methods (such as sunlight pattern, microscope, and photoelectriccell) are discussed. The paper then treats in detail with the FM methodand describes the FM calibrator. A comparison of FM and optical calibratorsis included together with discussions on change in frequency responsedue to cutting load, change in recording level with groove width,distortion, and monitoring.(6 pages; 10 figures)"'Decimal Classification: R681.843.f Broadcast News, June, 1946.