Cables distortions

In the cathodic protection of asymmetrically connected communication cables, distortions are coupled into the transmission lines coming from the ripple of the sheath current. In this case also, limiting the residual ripple to 5% is usually sufficient. 

In these and other applications where the coiled cable distorts or interferes with the accuracy of acquired data, a shielded coaxial cable should be used. While these non-coiled cables can be more difficult to use in conjunction with a portable analyzer, they are essential for low-speed and electromagnetic field applications. 

Operated broadband amplifier 1, has uniform (not worse than 1 dB) frequency feature within the range of 1 to 50 MHz and the range of reinforcement from 0 to 90 dB. The input cascade has an impedance switch that enables to matching of sensors of different types and to avoid signals and distortions caused by the cable. 

Doors and windows removed. Some frame distortion to steel frame buildings and cladding removed. Some electrical/instniment cables broken. ... 

Note Wherever a cable lead connecting the above devices (such as for RTDs) has to pass through a magnetic field, it may be screened with tinned copper-braided wires to nullify the effect of stray fields. The field may distort the readings. 

Electromagnetic (EM) Conductivity Measures the electrical conductivity of materials in microohms over a range of depths determined by the spacing and orientation of the transmitter and receiver coils, and the nature of the earth materials. Delineates areas of soil and groundwater contamination and the depth to bedrock or buried objects. Surveys to depths of SO to 100 ft are possible. Power lines, underground cables, transformers and other electrical sources severely distort the measurements. Low resistivities of surficial materials makes interpretation difficult. The top layers act as a shunt to the introduction of energy info lower layers. Capabilities for defining the variation of resistivity with depth are limited. In cases where the desired result is to map a contaminated plume in a sand layer beneath a surficial clayey soil in an area of cultural interference, or where chemicals have been spilled on the surface, or where clay soils are present it is probably not worth the effort to conduct the survey. 

A number of equipment problems can result in bad or distorted data. In addition to the surge and spike discussed in the preceding section, damaged cables, transducers, power supplies, and other equipment failures can cause serious problems. Therefore, it is essential to verify all data throughout the acquisition process. 

Unfortunately, not all distortions of acquired data result in a low-level alert. Damaged or defective cables or transducers can result in a high level of low-frequency vibration. As a result, the low-level alert will not detect this form of bad data. However, the vibration signature will clearly display the abnormal profile that is associated with these problems. 

Samples are normally exposed in a vertical orientation. If samples melt and drip, the heat can be redirected, by means of a system of aluminum foil mirrors, towards a horizontal sample. Many of the materials used for the series of experiments reported here melted excessively, away from the flame. Therefore, vertical burns were impossible for them, without distorting the data. All the materials investigated in the OSU RHR calorimeter, with the exception of the experimental flexible vinyl wire and cable compound, were, thus, exposed horizontally. 

Also, remember that the general form expression for the individual harmonic distortions states that /n is equal to the RMS value of the nth harmonic current divided by the RMS value of the fundamental current, thus an expression for the current rating factor for cables can be formulated. The current rating factor (q) is the equivalent fundamental frequency current at which the cable should be rated for carrying nonlinear loads containing harmonic frequency components ... 

Coaxial cables are commonly used as low-distortion, low-jitter delay lines in timing circuits. The velocity of a current pulse along an ideal cable (Ro, G0 = 0) is given by c = (L0C0)"I/2 2xl08 ms 1. Hence a pulse takes almost exactly 5ns to travel along lm of cable-a handy figure to remember. 

Power lines, underground cables, transformers and other electrical sources severely distort the measurements. 

For high precision measurements however, the influence of minor distortions of cable positions, of the dimensions of the sample (e.g. the deviations/curvature of the lines of the electric field E at the edge of the sample) or of minor changes in the characteristics of the electronic devices (e.g. temperature effects) can not be neglected. 

Microbending Loss. As a result of their small diameters, optical fibers bend very readily. This feature is advantageous in that the transmission medium is very flexible and easily routed. However, when the spatial period of the bending becomes small (approx. 1 mm or less), some of the light rays normally guided by the fiber are lost through radiation. Such small period distortions may occur when a fiber is wound on a spool under tension or when it is placed in cable structure. The phenomenon is termed microbending (11), and... 

In practice the resistance of the inner and outer conductor and the dielectric loss of the insulator cause some loss at high frequency. The corresponding distortion of a pulse edge for the commonly used RG58 (4.9 mm thick) and RG174 (2.9 mm thick) cables is shown in Fig. 7.48. 

Fig. 7.48 Pulse edge distortion of a 2 ns pulse after propagation through 2.5 m RG 56 and RG 174 cable. The cable was terminated with 50 Q...

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