Phase

The term phase describes the position of the waveform relative to time 0. If we think of the waves as something that can be shifted backward or forward along the time axis, phase describes the amount of that shift.

Phase is measured in degrees or radians.

  • Undefined control sequence \degree rad

  • Undefined control sequence \degree is Undefined control sequence \degree rad

  • rad is Undefined control sequence \degree

Phase Shifts:

  • a phase shift of Undefined control sequence \degree corresponds to a shift of a complete period

  • a phase shift of Undefined control sequence \degree corresponds to a shift of one-half of a period

  • a phase shift of Undefined control sequence \degree corresponds to a shift of one-quarter of a period

phase waves 3 sine waves with same amplitude and frequency but different phase

  • (a) A sine wave with a phase of Undefined control sequence \degree starts at time 0 with a zero amplitude. The amplitude is increasing.

  • (b.) A sine wave with a phase of Undefined control sequence \degree starts at time 0 with a peak amplitude. The amplitude is decreasing.

  • (c.) A sine wave with a phase of Undefined control sequence \degree starts at time 0 with a zero amplitude. The amplitude is decreasing.

Another way to look at the phase is in terms of shift or offset. We can say that:

  • (a.) A sine wave with a phase of Undefined control sequence \degree is not shifted.

  • (b.) A sine wave with a phase of Undefined control sequence \degree is shifted to the left by 1/4 cycle. However, note that the signal does not really exist before time 0.

  • (c.) A sine wave with a phase of Undefined control sequence \degree is shifted to the left by 1/2 cycle. However, note that the signal does not really exist before time 0.

A sine wave is offset cycle with respect to time 0. What is its phase in degrees and radians

We know that 1 complete cycle is Undefined control sequence \degree . Therefore, cycle is Undefined control sequence \degree rad