至今已经讨论了以基带信号功率源(例如,音频和视频信号)来改变射频(RF)载波幅度的问题。在调频中,频率(而不是幅度)以信号的速率改变。必须记得,在调幅(AM)中,调制信号的幅度变化越大,边带幅度的变化就越大。例如,调制信号是音频时,音频信号变化得越大,边带信号变化得就越大,从而 The issue of changing the radio frequency (RF) carrier amplitude with baseband signal power sources (eg, audio and video signals) has been discussed so far. In FM, frequency (not amplitude) changes at the rate of the signal. It must be remembered that in amplitude modulation (AM), the greater the change in amplitude of the modulated signal, the greater the change in the amplitude of the sideband. For example, when the modulation signal is audio, the greater the change of the audio signal, the larger the sideband signal changes, and thus