![<?echo $_SERVER['SERVER_NAME'];?>](/template/twentyseventeen/skin/images/header.jpg)
This article introduces the most common basic waveforms in audio synthesis. These basic waveforms are the basis for the sound of the voltage controlled oscillator (VCO) and low frequency oscillator (LFO) in analog sound synthesis. Of course, in digital audio synthesis, it is also the most basic and need to understand the waveform.
1. Sine Wave
The sine wave has been introduced in general. It needs to be further explained that the sine sound is the purest sound. It consists of only a single frequency with a uniform level of strength, that is, there is only one fundamental frequency, which is itself, and no other overtones. The reason it is called "sine" sound is because in the graph display, the sine wave waveform vibration curve changes with the rule of the trigonometric sine curve.
2. Triangle Wave
The shape of the triangle wave contains two linear stages, so the overtone position of the triangle wave will fall in its odd places. If compared with a sine wave of the same frequency, the triangle wave sounds like C, E, G, B. The first overtone of the triangle wave can be clearly distinguished, and the other overtone energy is very small, so we often mistake the triangle wave Sine wave.
3. Sawtooth Wave
The shape of the sawtooth wave is similar to the triangle wave, but the sawtooth wave contains odd and even harmonics, but is divided into forward (PosiTIve Sawtooth) and reverse (NegaTIve Sawtooth).
4. Square Wave
The overtone of the square wave only falls in odd positions. The square wave has rich overtone content. Therefore, the sound effect produced by the square wave is in contrast to the sine sound, and it is widely used in classical studios. The square wave generator was not only popular in the early studios, but due to its rich sound resources, it has since become a standard device.
5. Pulse Wave
The pulse wave is formed by changing the square wave in the time domain by the length of the positive and negative stages to bring about the change of the frequency spectrum. Pulse waves are relatively close to square waves and have rich overtones, so some textbooks treat the two as a class. The biggest characteristic of the pulse wave is that it will adjust the number of overtones as the time domain changes and the set parameters. The amount of overtone depends on the change in the shape of the pulse wave.
In general, the sharper the curve of the waveform, the richer the spectrum content. Figure 5-6 shows two sounds with the same frequency but different waveforms, which will bring different channel spectrums and different tones.
6. Noise
From the point of view of objective physical phenomena, noise has a certain pitch compared with musical sound, and musical sound has a prominent harmonic spectrum, while noise contains a theoretically infinite and continuous frequency distribution. The waveform is not a regular periodic cycle, and the amplitude is any irregular fluctuation.
From the subjective point of view, noise generally refers to all sounds that the listener does not need subjectively. Any sound that is unnecessary for people, even if it is a musical tone, or a musical tone that I once liked, may be regarded as noise. Of course, the definition of noise often has a close relationship between subjective and objective.
In short, from the perspective of sound synthesis, noise has rich spectral content. This provides ideal materials for computer synthesis and processing, which is especially manifested in the subtraction synthesis described later. Therefore, for computer music, noise is a vital sound resource for electronic sound synthesis.
7. White noise
The so-called white noise (White Noise) refers to a sound signal, (generally noise) the amplitude strength of all frequencies corresponding to its frequency level. That is, the high-frequency amplitude is relatively high, and the low-frequency amplitude is relatively low. White noise is sometimes referred to as white sound. The etymology is derived from the word "white light" in optics. White light refers to an optical phenomenon that presents all spectra simultaneously.
Pure white noise is almost absent in the real physical world, it can only be generated by a white noise generator. Due to its rich frequency spectrum and huge plastic space, it has been a very useful sound resource in computer sound synthesis.
A white noise spectrum whose frequency varies in three octaves. It can be seen that its characteristic is that as the frequency increases, its amplitude energy also increases. Corresponding to this is Pink Noise, its amplitude does not change with frequency, and the amplitude energy of each octave frequency is the same.
Solar LED land lamp uses sunlight as the energy source, charges during the day and uses at night, does not need complex and expensive pipeline laying, can arbitrarily adjust the layout of lamps and lanterns, safe and energy-saving, pollution-free, stable and reliable without manual operation, saving electricity and maintenance. Solar LED street lamp is mainly composed of solar cell module (including bracket), LED lamp holder, control box (with controller, battery) and lamp pole.
Solar Led Street Light,Street Light Lamp,Solar Powered Street Lights,Solar Powered Led Street Lights
Yangzhou Heli Photoelectric Co., Ltd. , https://www.heli-eee.com