| 摘要 |
PROBLEM TO BE SOLVED: To properly carry out the spectrum display of power even for an input signal with a large dynamic range by allowing the received signal to be subjected to logarithmic amplification, detection, and A/D conversion, and by performing antilogarithm conversion to the power value of the dimension of a watt for each display point in the width of frequency sweeping for obtaining an average power value. SOLUTION: An antilogarithm conversion part 31 converts a measurement value for the ith display point to the antilogarithm of the dimension of a watt by the nth sweeping. A digital value being converted by an A/D converter 17 is stored into a memory 18, and the digital value is converted by a dBm conversion part 32 for converting to the antilogarithm with dBm (decibel value) as a unit. An average value calculation part 34 adds the antilogarithm being converted by the antilogarithm conversion part 31 to the ith antilogarithm addition value up to the previous sweeping in an addition value memory 33, and at the same time divides the addition value of the antilogarithm up to nth time for obtaining an average value. A logarithm conversion part 35 calculates the logarithm of the average value for obtaining the display data of a display point (i), for storing into a logarithmic value memory 37, and at the same time for displaying at the display point (i) of a display 24.
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