Noise interference

Noise rating. One of a series of curves relating noise level and frequency to speech interference Noise criteria. Similar to NR, but differing, particularly at the low-frequency end... 

Fig. 40.18. Noise characterisation in the frequency domain. The power spectrum IF(v)l of three types of noise, (a) White noise, (b) Flicker or 1//noise, (c) Interference noise.

Polystyrene capacitors have exceptionally low tan S values (< 10 q, making them well suited for frequency-selective circuits in telecommunications equipment. Polymer capacitors are widely used for power-factor correction in fluorescent lighting units, and in start/run circuitry for medium-type electric motors used in washing machines, tumble-dryers and copying machines for example. They are also used in filter circuits to suppress radio frequencies transmitted along main leads. Such interference noise may originate from mechanical switches, furnace controllers and switch mode power supplies it not only spoils radio and television reception but can also cause serious faults in data-processing and computer equipment. 

Intrinsic noise can only be minimized by selecting low noise components or by using statistical methods if it is possible to make repeated measurements. Normally, the user of a data acquisition system has no influence on its construction. Therefore we will only consider the interference noise in the discussion below. A short survey on methods for noise reduction is given by Smit (ref. 9). 

Identity matrix, 206 Integration, 62 Simpson s method, 64 Interference noise, 31 Interpolation, 47 linear, 47 polynomial, 48 spline, 50... 

Interference noise , resulting in contributions at well-defined frequencies and mostly stemming from components in the system. 

II. ICP/SPD The noise of the ICP/SPD detection system is practically independent of the plasma background level, i.e., it is radiofrequency interference noise, or more generally readout noise, limited. Therefore, because the net analyte signals drop with wavelengths, Figure 17, so do also the S/N values, and the detection limit values are raised. As previously discussed, a nearly linear improvement in detection limit can be achieved with an increase in integration time (See Table IV). 

There are numerous sources of noise that arise from instrumentation, but briefly the noise will comprise flicker noise, interference noise, and white noise. These classes of noise signals are characterized by their frequency distribution. Flicker noise is characterized by a frequency power spectrum that is more pronounced at low frequencies than at high frequencies. This is minimized in instrumentation by modulating the carrier signal and using a.c. detection and... 

F. 8. Noise power spectra commonly found in chemical instrumentation. (A) "white noise (B) flicker (1//) noise and (C) interference noise. (Reprinted with permission from Ref [36].)... 

A) White noise B) Flicker (I//) noise C) Interference noise 1311... 

Both nonfundamental and interference noise can often be eliminated by appropriate filtering. 

Limiting the level of electromagnetic interference (noise) emanating from electronic systems and subsystems. 

Fig. 123. Optical reflection spectra of YbS at 6, 47 and ll6kbar. The vertical dashed lines indicate the energy below which interference noise is observed. The spectra are not corrected for losses at the diamond face. (After Syassen et al. 1985.)...

Such laser beam noises can be suppressed by modulating the laser power at a high frequency (typically 300-500 MHz). The laser modulation changes the laser oscillation mode from the single mode to the multimode. As the optical feedback noise arises from the competition between the different laser oscillation modes (i.e., mode hopping), multimode oscillation is effective to suppress the optical feedback noise. In addition, multimode oscillation reduces the coherence length (f ch) of the laser beam, which is effective to suppress the interference noise at the PSPD surface. 

This challenge is of great interest when the bit error rate (BER) is variable along the same codeword. In addition to VHM, FUEC codes may also result of interest in automotive, aerospace or avionics industries, where different sources of interference, noise or process variations may result in areas with variable BER (vBER). In these applications, intermittent faults in VLSI circuits increase the fault rate in the affected bits. In addition, the occurrence of multiple faults makes necessary to consider diverse error patterns in data storage and transmission. 

If the electrode s tip is in the subglottic cavity, the electromyographic machine produces a large amount of interference noise. If the electrode is too deep, it may reach the lateral cricoarytenoid muscle. 

Low frequency noise is below 10 Hz and is largely generated by the sample introduction system (peristaltic pumps, nebulisation). High frequency noise is above 10 Hz and is related to the gas dynamics of the ICP and desolvation in and before the plasma or to interference noise from the AC line voltage. White noise represents the background in a noise amplitude spectrum and occurs for all possible frequencies. A noise amplitude spectrum shows the frequency composition of the noise for the entire spectrometric system (noise amplitude versus frequency). Other fluctuations can be drift effects, which affect sensitivity and mass discrimination. 

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