Frequency accuracy

Current accuracy Frequency response 0.2% of full scale (2% for 1-10 nA current ranges)... 

The PCB-based planar coil (a set of five coils is shown in Fig. 2) with N = 40 turns (diameter D = 12 mm) have been selected for further investigation. This type of coils has the most appropriate high accuracy frequency response up to 500 kHz and with a reasonable accuracy up to 10 MHz. 

Information reliability Information accuracy/frequency/ credibility Chen etal., 2000b. 

In this work, a microwave interferometric method and apparatus for vibration measurements is described. The principle of operation is based on measurement of the phase of reflected electromagnetic wave changing due to vibration. The most important features of the method are as follows simultaneous measurement of tlie magnitude and frequency of the rotating object high measurement accuracy weak influence of the roll diameter, shape and distance to the object under test. Besides, tlie reflecting surface can be either metallic or non-metallic. Some technical characteristics are given. 

Almost all microwave methods are non-contact [1] and allow simultaneous measurement of the magnitude and the frequency of vibrations. The distance between the inspected surface and microwave sensor can vary from several millimeters to a few meters. However, the accuracy of the measurement of vibration magnitude also depends on a distance between the microwave sensor and the object as well as the shape of the inspected surface. 

The screen shows the predefined area to be scanned and filled to ensure maximum coverage The transmitter operates with a frequency of 40 kHz and with a pulse repetition frequency of 200 Hz. This gives the system an accuracy in positioning of better than 1 mm. 

The many approaches to the challenging timestep problem in biomolecular dynamics have achieved success with similar final schemes. However, the individual routes taken to produce these methods — via implicit integration, harmonic approximation, other separating frameworks, and/or force splitting into frequency classes — have been quite different. Each path has encountered different problems along the way which only increased our understanding of the numerical, computational, and accuracy issues involved. This contribution reported on our experiences in this quest. LN has its roots in LIN, which... 

Step size is critical in all sim tilation s. fh is is th c iricrcm en t for in tc-grating th c equation s of motion. It uitim atcly deterrn in cs the accuracy of the numerical integration. For rn olecu les with high frequency motion, such as bond vibrations that involve hydrogens, use a small step size. 

For very-high-accuracy ah initio calculations, the harmonic oscillator approximation may be the largest source of error. The harmonic oscillator frequencies... 

The following table shows the accuracy of computed fundamental frequencies for CO2 (cm" ) ... 

Molecules such as 3,4 and 5 in Figure 2.6, which have a zero velocity component away from the source, behave uniquely in that they absorb radiation of the same frequency Vj-es whether the radiation is travelling towards or away from R, and this may result in saturation (see Section 2.3.4). If saturation occurs for the set of molecules 3, 4 and 5 while the radiation is travelling towards R, no further absorption takes place as it travels back from R. The result is that a dip in the absorbance curve is observed at Vj-es, as indicated in Figure 2.5. This is known as a Lamb dip, an effect which was predicted by Lamb in 1964. The width of the dip is the natural line width, and observation of the dip results in much greater accuracy of measurement of v es. 

Direct Mass Measurement One type of densitometer measures the natural vibration frequency and relates the amplitude to changes in density. The density sensor is a U-shaped tube held stationaiy at its node points and allowed to vibrate at its natural frequency. At the curved end of the U is an electrochemical device that periodically strikes the tube. At the other end of the U, the fluid is continuously passed through the tube. Between strikes, the tube vibrates at its natural frequency. The frequency changes directly in proportion to changes in density. A pickup device at the cui ved end of the U measures the frequency and electronically determines the fluid density. This technique is usefiil because it is not affec ted by the optical properties of the fluid. However, particulate matter in the process fluid can affect the accuracy. 

When the data do not warrant the accuracy of Eq. (9-89) or Eq. (9-90), simpler cui ves will usually suffice if the frequency distribution may be assumed to have a single maximum value. 

The effect of pulsating flow on pitot-tube accuracy is treated by Ower et al., op. cit., pp. 310-312. For sinusoidal velocity fluctuations, the ratio of indicated velocity to actual mean velocity is given by the factor /l + AV2, where X is the velocity excursion as a fraction of the mean velocity. Thus, the indicated velocity would be about 6 percent high for velocity fluctuations of 50 percent, and pulsations greater than 20 percent should be damped to avoid errors greater than 1 percent. Tne error increases as the frequency of flow oscillations approaches the natural frequency of the pitot tube and the density of the measuring fluid approaches the density of the process fluid [see Horlock and Daneshyar, y. Mech. Eng. Sci, 15, 144-152 (1973)]. 

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