| 摘要 |
PURPOSE:To make it possible to quantitatively measure the modulation degree of a fundamental center frequency value not by the analogue quantity of timewise change but in conformity with a FM wave theory, by precisely measuring a spectral component around the fundamental center frequency value of a certain frequency signal. CONSTITUTION:At first, a spectral component with a certain fundamental center frequency fK is continuously calculated through a calculation means 6 by the setting operation of a specific frequency setting dial, 1 a sampling frequency setting dial 2 and a frequency dissolving power setting dial 3 and displayed on a display means 8 in an on-line system. Next, by adjusting a frequency venier dial 4, a data obtaining time width T is changed by a minute amount DELTAT to perform the minute amount movement of the fundamental center frequency fK and the spectral component around the frequency fK is observed in detail. The magnitude of thus obtained spectral quantity of a side band is compared with that of the spectral quantity of the frequency fK and, subsequently, a table of Bessel function is utilized to calculate the magnitude of the frequency modulation degree to each modulation component corresponding to the side band by an algorithm calculation means.
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