. An elementary manual of radiotelegraphy and radiotelephony for students and operators . ry rapidly, unless oscillations of two frequenciesoccur in the circuit under test, in which case there will be twopeaks (see Fig. 16). Let a^ be the mean-square value of the current in thecymometer, in any position of the handle corresponding to whichthe natural period of frequency of the cymometer is n^, and let A?denote the mean-square value of the maximum current in thecymometer when it is tuned to resonance with the circuit undertest, and let n^ denote the corresponding frequency as readon the cymomet
. An elementary manual of radiotelegraphy and radiotelephony for students and operators . ry rapidly, unless oscillations of two frequenciesoccur in the circuit under test, in which case there will be twopeaks (see Fig. 16). Let a^ be the mean-square value of the current in thecymometer, in any position of the handle corresponding to whichthe natural period of frequency of the cymometer is n^, and let A?denote the mean-square value of the maximum current in thecymometer when it is tuned to resonance with the circuit undertest, and let n^ denote the corresponding frequency as readon the cymometer. Then the oscillation circuit under test hasa certain decrement Si, and the cymometer itself has a certaindecrement ca. It has been shown by \. Bjerknes and P. Drude that the 320 RA DIO TELEGRA PH Y following relation holds good between the decrements of the twocircuits and the frequencies n\ and ?i2, viz.: gl + g, = TT (l - A^ - oC^ provided that nx and n^ do not difier from one another by morethan, say, five per cent. Since the frequency is connected with the oscillation constant. Fig. 16,—A Kesonance Curve. by the formula n = 5-033 X 10^0 we can also write the above formula of Prude and Bjerknes in the following form: O2-O1 /~Z^ O2 V A=^ - a2 ^1 + ^2 = 3-1416 Plotting out the resonance curve as above described, it is bestto take the mean-square value of the maximum curve as unity,and to correct the other currents in the corresponding ratio; andthe same way for the frequencies, viz. the resonance frequency RADIOTELEGRAPHIC .\fEASUREMESTS y.\ and any other frequency. If, then, we put x f<r (l - ^^) and y for , we Ciin write the ubuvo foruiuhi for the sum of theA. decrements tiually in the form V gx + c, = 3141G a* ^ • -; Since the resonance curve is not quite symmetrical with respectto its maximum ordinate, it is best to determine from the resonancecurve the values of the frequency n-i lying on either side of themaximum current, wliieh correspond to any {,iven value
Size: 1593px × 1569px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1916
