Sine wave
Sine waves are signals that oscillate smoothly either side of a central value - normally zero volts.
The sine wave follows the values of sine over the period of the cycle. As one cycle is equivalent to 360° or 2Π radians, the instantaneous value of sine can be calculated from the angle in degrees or radians, i.e. how far advanced the waveform is in its cycle.
Parameters like the phase angle, amplitude, time period and the like can all be seen.
Time domain of Sine wave
Frequency domain of Sine wave
It has only one harmonic.
Square wave
Square waves switch between two values. Square waves have the same amount of time in each state. Strictly speaking a square wave is one that is square and has equal times on either state, i.e. it has a 1:1 mark to space ratio. A rectangular waveform(Pulse wave) is a periodic two state waveform that has unequal mark to space ratio.
When used in a logic or digital circuit the two states are often designated as "1" and "0" corresponding to the binary digits. They may also be referred to as "HIGH" and "LOW" indicating the voltage.
Important characteristics of a square waveform apart from the amplitude and frequency / period are the rise and fall times of the edges.
Time domain of Square wave
Frequency domain of Square wave
The amplitude spectrum of the square wave consists of only odd harmonics smae as the case for the triangle.
The amplitudes of square’s harmonics decay slower than in the case of the triangle: they decay as 1/, where is the harmonic’s index ( corresponds to the fundamental).
Triangle wave
A triangular waveform rises and then falls. The most common form of triangular waveform rises and then falls at the same rate, although it is possible for the rise and fall rates to be different if required.
The rise and fall are linear lines and the transition between rise and fall is near instantaneous.
Time domain of Triangle wave
Frequency domain of Triangle wave
The amplitude spectrum of the triangle waveform contains only odd harmonics.
The amplitudes of the harmonics decay as 1/, where is the harmonic’s index (the fundamental has , the first overtone has , and so on).
Sawtooth (ramp) wave
A sawtooth or ramp waveform is one which rises to its final value and then falls away with a near vertical drop. This gives a positive ramp waveform.
It is also possible to have a negative ramp where the signal slowly falls from a maximum to the low value and then rises with a near vertical slope to the maximum value again.
Time domain of Sawtooth wave
Frequency domain of Sawtooth wave
The spectrum of the sawtooth waveform contains odd and even harmonics. The amplitudes of sawtooth’s harmonics decay as 1/, where is the harmonic’s index ( corresponds to the fundamental frequency).
출처:
https://thewolfsound.com/sine-saw-square-triangle-pulse-basic-waveforms-in-synthesis/
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