Pink noise

Amplifier noise. Can be of two kinds white noise results from random fluctuations of signal over a power spectrum that contains all frequencies equally over a specified bandwidth pink noise results when the frequencies diminish in a specified fashion over a specified range. 

The measurement of the electrode impedance has also been ealled Faradaie impedanee method. Since measurements are possible by applying either an electrode potential modulated by an AC voltage of discrete frequeney (which is varied subsequently) or by applying a mix of frequencies (pink noise, white noise) followed by Fourier transform analysis, the former method is sometimes called AC impedance method. The optimization of this method for the use with ultramicroelectrodes has been described [91Barl]. (Data obtained with these methods are labelled IP.)... 

In 1// noise or pink noise, the noise is inversely proportional to the frequency v that is, it has the distribution function... 

Flicker-noise spectroscopy — The spectral density of - flicker noise (also known as 1// noise, excess noise, semiconductor noise, low-frequency noise, contact noise, and pink noise) increases with frequency. Flicker noise spectroscopy (FNS) is a relatively new method based on the representation of a nonstationary chaotic signal as a sequence of irregularities (such as spikes, jumps, and discontinuities of derivatives of various orders) that conveys information about the time dynamics of the signal [i—iii]. This is accomplished by analysis of the power spectra and the moments of different orders of the signal. The FNS approach is based on the ideas of deterministic chaos and maybe used to identify any chaotic nonstationary signal. Thus, FNS has application to electrochemical systems (-> noise analysis). 

Pink noise broadband noise whose energy content is inversely proportional to frequency (-3dB per octave or -10 dB per decade). 

The two constraints that make direct observation of weak absorption signals impracticable are the presence of pink noise, which contains a preponderance of low-frequency power compared with white noise, and the enhancement of this and other sources of noise by the rectification process through which MMW signals are detected. Both predicate the use of some kind of modulation at a frequency greater than the noise comer frequency and the use of a phase-coherent detector to convert the resulting modulated signal to a DC level suitable for display or for post-detection computer processing. 

The primary sources of noise in this region are classified as thermal or Johnson noise together with shot noise due to the particulate nature of photons and electrons. Additionally there is non-equilibrium or inverse frequency noise, often termed pink noise to distinguish it from the other two that have a uniform white noise frequency distribution. 

Track 23] Inharmonic Sounds Synth Bell, Stone Tile, Djembe Drum. [Track 24] White Noise, Pink Noise, Whispered ahh and eee. ... 

Track 24] White Noise, Pink Noise, Whispered ahh and eee. ... 

Also included in the Detector Module is the 1/f noise or pink noise. It is defined by the knee frequency, ft, at which the noise level has increased by a factor of /2 compared to the white noise level, e . Figure4.13 shows a typical 1/f noise power spectrum for different values of the knee frequency. 

So far, we have assumed FAIMS waveforms to follow the ordained U(t) dependence. The waveforms produced by real electronics always carry unwanted oscillations (electronic noise) of diverse physical origin, including thermal, shot, and inductive coupling of instmmental and environmental RF. Thermal ( white ) noise has uniform power spectrum that allows unbiased gauging of the impact of noise on FAIMS performance. Other noises appear over limited fiequency ranges ( pink noise) or at specific frequencies such as overtones of harmonics comprising Ed(0 or the industrial AC power frequency (60 Hz in USA) and its overtones. The spectra of those noises are sensitive to specific FAIMS hardware and lab environment. The effect of noise ceases above some frequency because ions have not enough time to respond. Based on the relaxation time estimates (3.2.1),... 

White noise, pink noise, blue noise, flicker noise... 

With studs of low torsional rigidity, such as steel channels, sound transmission via the studs appears to be negligible. The simpler constructions have been tested by several laboratories, and results have been found to be reasonably reproducible. The test specimens were mounted and caulked into an opening 10-ft wide by 8-ft high that separated two reverberation rooms. The test signal consisted of third-octave bands of pink noise. 

The above consideration does not encompass the very important f noise (flicker noise, current noise, modulation noise). It is marked at lower frequency ( pink noise ) and becomes negligible in comparison to g-r noise at a knee frequency, a value that may be anywhere between several Hz and 100 MHz, depending on a particular device. In a general case flicker noise is given by the general empirical relation [64]... 

If the readouts from both of the contact pairs are lead to separate preamplifiers, brought into counterphase and lead to an addition circuit, pink noise will be removed, since it is correlated on both channels, but the signal will remain, since it exists on only one of the contacts. 

Fig. 1.1 Complexity degrees of - noise with white noise (b = 0), pink noise b = 1), red noise (b = 2), and black noise b = 3) [22] (Color figure online)...

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