Angle modulation

Japanese: 角度変調 - かくどへんちょう（英語表記）angle modulation

A general term for phase modulation (PM) and frequency modulation (FM). When the modulating signal is v ( t ), a method in which the phase _θc of a sine carrier wave is proportional to the modulating signal itself, i.e., _θc = ⊿θv ( t ), is called phase modulation. A method in which the phase _θc is proportional to the integral value of the modulating signal, i.e., is called frequency modulation. Therefore, if the modulating signal is integrated before being input to the phase modulator, it becomes FM. For this reason, when the modulating signal is analog, PM and FM have almost the same properties. On the other hand, when the modulating signal is digital, the above formula also holds, but the properties of phase modulation and frequency modulation are quite different, so the term angle modulation is not often used.

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

位相変調PMと周波数変調FMの総称。変調信号をv(t)としたとき，正弦搬送波の位相θ_cが，　θ_c＝⊿θv(t)と変調信号自体に比例する方式を位相変調という。また，位相θ_cが，　と変調信号の積分値に比例する方式を周波数変調という。したがって，変調信号を積分してから位相変調器に入力すれば，FMとなる。このため，変調信号がアナログの場合，PMとFMは，ほぼ同じ性質を有している。一方，変調信号がディジタルの場合，上述の式はやはり成り立つが，位相変調と周波数変調の性質はかなり異なるため，角度変調という用語はあまり使われない。

出典　株式会社平凡社世界大百科事典第２版について　情報

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