| 摘要 |
<P>PROBLEM TO BE SOLVED: To simultaneously read a modulation system, an interference status and a transient phenomenon from display of a spectrum analyzer 12 of a radio set 10. Ž<P>SOLUTION: A local oscillator 33 provides an upward ladder-like sweep local oscillation signal to a mixer 32. A primary IF signal is down converted at the mixer 32, is passed through a band pass filter 34 and becomes a secondary IF signal. Each secondary IF signal is associated with a frequency division obtained by dividing a span of a spectrum analyzer 12 and supplied to a signal processor 40 after A/D conversion. A local oscillator 44 supplies a downward ladder-like sweep local oscillation signal to the mixer 32. A mixer 43 deploys the secondary IF signals in a frequency axis direction in the order of frequencies for each frequency division. A buffer adder 49 totals the deployed IF signals for each frequency division and a power spectrum calculation section 51 performs FFT on a total value. On the basis of a result of the FFT, a power spectrum is displayed on an indicator 54. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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