| 摘要 |
PROBLEM TO BE SOLVED: To properly judge from a first input signal that it is a phase modulated signal. SOLUTION: A first spectrum width measuring device 5 measures a spectrum width of an input signal from a reverse wave tracking device to a first system 2. A second spectrum with measuring device 8 measures a spectrum width of the input signal through a second, a third systems 3, 4, an adder 6 and a high frequency filter 7. A comparator 9 compares the spectrum width from the first spectrum measuring device 5 with the spectrum width from the second spectrum-measuring device 8, and judges in accordance with a relationship of the spectrum widths, small or larger, whether the input signal is a non- modulated signal or a shape modulated signal. |
