Noise spikes

Liquid samples may be sealed in ampules, tubing, or capillaries depending on the amount of the sample available (Fig. 2-20B). For microquantities ( 10 9 liter), capillaries as small as 0.5-0.1 mm bore and 1 mm in length have been used. Use of a large cylindrical cell, such as that shown in Fig. 2-20C, reduces local heating and allows more accurate determination of depolarization ratios. Strong spike noise may appear if the solution contains solid particles. 

For the media preparation, 25-nm-thick CoZrNb soft magnetic film was sputtered onto Ni-P SUL and then a thick CoPtCr-SiC>2 granular recording layer. For comparison, a media with 200-nm-thick sputtered CoZrNb SUL was used. The results showed that an electroless-deposited ferromagnetic Ni-P layer (low phosphorus content), which is suitable for mass production as a SUL for a double-layered perpendicular recording media, exhibits almost the same magnetic properties and recording performances as a 200-nm-thick sputtered SUL. In addition, the spike noise which is commonly observed from SUL was not found for the media with Ni-P SUL. 

The magnetic field was applied in the direction parallel to the surface of disk substrate while the disk substrate was rotated. The Co-Ni-Fe-P SUL deposited without the magnetic field tends to show clear and complicated magnetic domain boundaries, whereas, the SUL deposited with the magnetic field has no marked domain boundaries. The magnetic domain boundaries of the former are readily moved by an imposition of an external magnetic field, and the domain boundaries cause an problem of spike noise. On the other hand, no domain boundaries are induced in the latter even when the external magnetic field was imposed. 

However, in a magnitude of root-mean-square noise amplitude, i.e. DC noise, the SUL without the generation of spike noise takes poor level. Figure 7.3 shows a variation in DC noise voltage of the Co-Ni-Fe-B SUL with in-plane coercivity. DC noise was increased with increasing the value of coercivity [18]. Since the coercivity... 

Fig. 7.5 Noise spectra for electrolessly Co-Ni-Fe SULs. 1 SUL without the generation of spike noise (stripped magnetic domain emerged film), 2 Dual layered SUL, 3. SUL with the generation of striped magnetic domain (low H film) [20]...

The dirt layer increases the formerly smooth surface area. The UV detection cell becomes an air collector and small air bubbles, possibly present in the mobile phase, are restrained and grow to a larger air bubble, resulting in spikes, noise and baseline drift and jumps. 

H Takeuchi, S Hashimoto, I Harada. Simple and efficient method to eliminate spike noise from spectra recorded on charge-coupled device detectors, Appl Spectrosc 47 129-131, 1993. 

Cosmic rays passing through the photosensitive region can produce thousands of photoelectrons. This effect results in a very strong sharp signal in the Raman spectrum. Quantification of spike noise is difficult due to the random nature of its occurrence. However, it is usually quite obvious to the observer when a spectrum of biological tissue contains a contribution from spike noise. These spikes can be erased from the spectrum or the whole spectrum can be discarded. They can also be circumvented by averaging several scans. 

By taking the mean positions of the peaks, it is seen that they are only 2.1 sec apart. However, as a result of a noise spike on the front of the... 

Example 60 If compound samples that were actually composed of five individual tablets had been analyzed instead of the spiked matrix, the CV would be expected to be larger than 0.5% on account of the additional manufacturing error, but by a factor Vs = 2.2 lower than the content uniformity CV. (Cf. Eq. (1.5).) Since the average CV for CU was found to be -1.76% ( 1.97, 1.28, resp. 1.95%), this would have to be in the region of about 1.76/2.2 = 0.8, which is still well within the range of accepted instrumental noise. 

A systematic analysis of a process signal over (1) different segments of its time record and (2) various ranges of frequency (or scale) can provide a local (in time) and multiscale hierarchical description of the signal. Such description is needed if an intelligent computer-aided tool is to be con--structed in order to (1) localize in time the step and spike from the equipment faults (Fig. 1), or the onset of change in sensor noise characteristics, and (2) extract the slow drift and the periodic load disturbance. 

The first term measures the difference between the data and the fit, KF. The second term is a Tikhonov regularization and its amplitude is controlled by the parameter a. The effect of this regularization term is to select a solution with a small 2-norm 11 F 2 and as a result a solution that is smooth and without sharp spikes. However, it may cause a bias to the result. When a is chosen such that the two terms are comparable, the bias is minimized and the result is stable in the presence of noise. When a is much smaller, the resulting spectrum F can become unstable. 

However, they do generally require an effective peak detection routine to ensure that both large and small key peaks are used, and that noise spikes are not detected as peaks. The reader is referred to Jarman et al.16 for a discussion and comparison of some different peak detection routines applied to MAID I data of bacterial samples. 

There are several other problems that can occur with uv flow cells. Air bubbles in the cell can produce a series of very fast noise spikes on the chromatogram, or pronounced drift in the baseline, followed by sudden changes in the baseline position, or both effects at once. 

A verification of the effects is seen in Figures 44-9a-l and 44-9a-2 which is also an investigation that is part of our original plan, and is presented in Figure 44-10a where we present a graph showing the transmittance noise as a function of the sample transmittance (If/If). As we see, except for the occasional spike, when the S/N ratio is... 

Once generated, these noise spikes cannot only appear on the input/output rails (causing related performance issues), but also infiltrate the IC control sections, causing it to behave anomalously, and unpredictably. We could even end up briefly losing the usual current limiting function too, leading to disastrous consequences. 

Note It is almost impossible to see the noise spikes. First of all, various parasitics help limit/absorb them somewhat (though they can still retain the capability to cause controller upset). Further, the moment we put in an oscilloscope probe, the 5 to 20pF of probe capacitance can also absorb the spikes sufficiently, and we would probably see nothing significant. In addition, probes pick up so much normal... 

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