Series noise

Figure 4.16, the effect of poor charge collection would be added to the series noise effect at low time constant. 

Series noise is those components of the noise that are considered to be in series with the detector signal. Shot noise in the preamplifier s PET is the prime source of series noise. It is equivalent to a voltage pulse generator in series with the signal at the input to an amplifying component. An alternative name is delta noise. The magnitude of series noise in the PET is described by ... 

Equation (6.7) indicates that to minimize series noise, we should ... 

While the thermal noise and the back-action noise are proportional to tm, the series noise is proportional to there is an optimal measurement time. 

Acoustical Louvers. Acoustical louvers are used in building mechanical systems when exterior walls are penetrated for fresh air intake, exhaust, or rehef air, in situations where the impact of HVAC noise is of concern in the surrounding environment. The louvers consist of a series of hoUow sheet metal blades. The bottom faces of the louver blades are perforated and the blades are filled with fibrous sound-absorbing material. Typical acoustical louvers are 20 cm (8 in.) to 30 cm (12 in.) in depth. The amount of insertion loss they provide is limited. 

Thorinm-232 is the only non-radiogenic thorium isotope of the U/Th decay series. Thorinm-232 enters the ocean by continental weathering and is mostly in the particulate form. Early measurements of Th were by alpha-spectrometry and required large volume samples ca. 1000 T). Not only did this make sample collection difficult, but the signal-to-noise ratio was often low and uncertain. With the development of a neutron activation analysis " and amass spectrometry method " the quality of the data greatly improved, and the required volume for mass spectrometry was reduced to less than a liter. Surface ocean waters typically have elevated concentrations of dissolved and particulate 17,3 7,62... 

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... 

Other forms of mechanical looseness increase the noise floor across the entire bandwidth of the vibration signature. While the signature does not contain a distinct peak or series of peaks, the overall energy contained in the vibration signature is increased. Unfortunately, the increase in noise floor cannot always be used to detect mechanical looseness. Some vibration instmments lack sufficient dynamic range to detect changes in the signature s noise floor. 

The corrosion process is observed as a series of events which all contribute to the overall corrosion rate. Measurement of rest potential fluctuations between two identical electrodes of potential fluctuations with respect to a fixed reference can be carried out. The electrochemical noise output spectrum is analysed using digitised data. The interpretation requires electrochemical expertise, and the method is therefore usually provided as a specialised service. 

PROS REJECT jcls Section 3.6, Fig. 1.29 In a production environment there are often several superimposed processes that yield measurement series like that depicted in the lower panel there is drift that unexpectedly changes slope, there is bias and measurement noise, and there are operators who take corrective action. The model includes the probability of drift occurring and a feed-back loop that permits both positive and negative coefficients. The operators can be ordered to react if a single value exceeds a set limit, or only if 2, 3, or more successive values do so. The program calculates the two-sided (asymmetric) total probability of a value being OOS and depicts this in the upper panel on a log(p) scale. The red horizontal is the upper limit on the total risk as set in cell B20. 

The most popular, and also a very accurate, experimental method for measuring nonselective spin-lattice relaxation-rates is the inversion recovery (180°-r-90°-AT-PD)NT pulse sequence. Here, t is the variable parameter, the little t between pulses, AT is the acquisition time, PD is the pulse delay, set such that AT-I- PD s 5 x T, and NT is the total number of transients required for an acceptable signal-to-noise ratio. Sequential application of a series of two-pulse sequences, each using a different pulsespacing, t, gives a series of partially relaxed spectra. Values of Rj can... 

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