41.1 Amplitude, Frequency, and Phase of a Sinusoidal Signal
An arbitrary sinusoidal signal can be written in the form:
where A Peak amplitude
f Frequency
Angular irequency
Phase at time t 0
This signai can be thought of as being the real part of a complex phasor that has amplitude A, and which rotates at a constant anguiar velocityo 2Trin the complex plane(see Flgure 30. Mathematically, then, s(n can be written as where 20 is the compiex phasor associated with s(t, and denotes the real part. The phase" of signal at any point in time corresponds to the angle that the rotating phasor makes with the real axis. The initial phase(i.e.. the phase ar time 0) is The"Irequency" roi the signal is 1/2T times the phasor's angular velocity