释义 |
single number dialing The AC waveform is a sinusoidal waveform, or sine wave, which is a wave that can be expressed as the sine of a linear function of time, or space, or both.The sine wave makes perfectly smooth transitions over time from zero to its maximum positive voltage, through zero, to its maximum negative voltage, and back again. An unmodulated sine wave continuously makes the same smooth transitions at the same frequency, and the same angle (phase) to the same maximum positive and maximum negative voltage levels. A sine wave can be modulated, or changed, through amplitude modulation (AM), frequency modulation (FM), or phase modulation (PM). Figure S-3 illustrates sine waves at various frequencies, but constant amplitude. |