White noise

White noise is a wave that vibrates irregularly and usually refers to noise in the audible band.

White noise has the same amplitude at every frequency. When seeing with acoustic power in a frequency band of a fixed width, the power of frequency becomes 3 dB/oct higher as the frequency becomes higher. Also, Pink noise is a filter that attenuates White noise by 3 dB/oct per frequency. In addition, the name of "white" is because light containing all frequencies is white color.

White noise is often used in technical fields such as sound adjustment and acoustic measurement, but it is also applied in various fields in medical fields and social fields. For example, by listening to white noise, symptoms of people suffering from tinnitus are alleviated, listening to noise such as masking sounds makes it easier for people with insomnia to fall asleep, concentration of works, it has been reported that there are better effects.

In the sound-related, the broadband noise signal (White noise and Pink noise) is commonly used. In order to perform more detailed measurement evaluation and tuning, it is also used the testing signal that has the specific subdivided frequency bands like a 1/1 or 1/3 octave band noise.

We have four types of applications that can generate White noise and Pink noise.　
- "Audio Tone Generator" : This app can generate generic audio reference signal.
- "Audio Tone Generator Lite" : Simplified "Audio Tone Generator", it is a free app. It has an advertisement display.
- "Audio Tone Generator for iPad" : This app can generate generic audio reference signal ustomized for iPad.
- "Octave Band Noise Generator/Lite" : By using white noise and pink noise as the source signal, it can generate a specific noise signal divided in frequency band by 1/1 or 1/3 octave band. Any frequency band can be programmably selected and output.