Microwave transmitter

Microwave interference (Doppler radar) techniques may be used to measure the velocity and displacement of the projectile in the barrel and its velocity over its entire trajectory. The basic system consists of a microwave transmitter... 

In the case of pulverized coal flow measurement, the concentration of the pulverized coal is measured by low-power, low-frequency microwave sensors. The variation in the microwave transmission characteristic (dielectric load) is caused by the changing coal concentration, which produces shifts in measurement frequency. The resulting quantifiable values indicate the coal density. This concentration measurement is performed by a microwave transmitter and a microwave receiver, as shown in Figure 3.90. The velocity of the pulverized coal is measured by two identical microwave devices by crosscorrelation. Here, the pair of sensors detect the stochastic signals resulting from the charged coal particles, which are nearly identical but shifted by the time the pulverized coal gets from one sensor to the other. 

High antenna gain means that microwave transmitters need not be extremely powerful to produce a strong... 

The cooling system is vital to any RF generator. In a high-power microwave transmitter, the cooling system may need to dissipate as much as 70% of the input AC power in the form of waste heat. For vapor phase-cooled devices, pure (distilled or demineralized) water must be used. Because the collector is usually only several volts above ground potential, it is generally not necessary to use deionized water. 

Battery power requirements to some extent depend on the mass of the satellite, which includes the weight of microwave transmitters, receivers, antennas, signalprocessing equipment, electronic sensors, onboard electrical appliances, solar panels and associated components, and the stabilization system. Two distinct types of stabilization system design configurations and associated components for satellite control are shown in Figure 2.6. Table 2.12 summarizes the battery power requirement and other critical parameters of commercial and military communications satellites. 

Radio-frequency radiation is emitted by microwave transmitters including ovens and radar installations. The body tries to cool exposed parts by blood circulation. Organs where this is not effective are at risk, as for infrared radiation. These include the eyes and reproductive organs. Where the heat of the absorbed microwave energy cannot be dispersed, the temperature will rise unless controlled by blood flow and sweating to produce heat loss by evaporation, convection and radiation. Induction heating of metals can cause bums when touched. 

Figure 3-10. Block diagram of the temperature jump NMR spectrometer equipped with a microwave transmitter. Microwave and radiowave coils in the probe head are also shown...

The frequency of microwave radiation lies between that of IR radiation and high frequency radio waves and the boundaries between these regions are not fixed [221]. The microwaves are generated in a transmitter (magnetron) which possesses a stalk which penetrates Uke a radio antenna into a hollow energy guide (Fig. 48). This leads the electromagnetic waves into the reaction chamber (power about... 

Fig. 5. Effect of magnet current on electrical resistivity and transmittance of SnOj film. Microwave power of 1600 W.

Fig. 6. Effect of microwave power on electrical resistivity and transmittance of Sn02 film. Magnet current of 160 A.

Automation equipment at the metering sites generate production volume information, indicate alarm and other equipment status, and provide some control capability. This equipment is connected to remote terminal units (RTU) at optimum points within the field by individual wire pairs of buried cable. The RTU s store the information generated and, on request from the computer, transmit it to the computer center by means of microwave or wireline. RTU s also receive messages from the computer for transmittal to appropriate equipment for execution. 

Microwaves and Radar yes yes liquids, powders, granular solids. Action very similar to ultrasonic signals. Has been employed for discrete sensing. Pulsed energy used in transmitted or reflected inodes. Transmitter and receiver can be mounted outside the vessel. Very useful for determining mean levels io closed vessels under difficult conditions, e.g. in cases of high turbulence, in the presence of vapour or condensate, or where there is encrustation of surfaces with deposits. Typical accuracies are of the order of 0.2 per cent FSD 1. 

When detecting the interface between two liquids, electrical conductivity, thermal conductivity, opacity, or sonic transmittance of the liquids can be used. Interface-level switches are usually of the sonic, optical, capacitance, displacer, conductivity, thermal, microwave, or radiation types. Differential pressure transmitters can continuously detect the interface, but, if their density differential is small relative to the span, the error will be high. On clean services, float- and displacer-type sensors can also be used as interface-level detectors. In specialized cases, such as the continuous detection of the interface between the ash and coal layers in fluidized bed combustion chambers, the best choice is to use the nuclear radiation sensors. 

Radar level transmitters and gauges use electromagnetic waves, typically in the microwave bands to make a continuous liquid and some solid level measurements. The radar sensor is mounted on the top of the vessel and is aimed down, perpendicular to the liquid surface. Most tank-farm gauges are operated on the FMCW principle (Figure 3.121). Other gauges and transmitters, particularly the lowest-cost units, are operated on the pulse principle. Both principles are fundamentally based on the time of flight from the sensor to the level of the surface to be measured. In the FMCW method, this time of flight is tracked on a carrier wave in the pulse method, it is the echo return. 

Although the soybeans used in this study were soaked prior to microwave treatment, this may not he necessary. It has been observed (Pour-El, personal communication) that irradiation of soybeans containing only innate moisture (6-7 ) for a period comparable to those used in this work reduced trypsin inhibitor levels by 90%. Allowing the microenvironmental water of the protein to be the energy transmitter reduced the time needed for inactivation. It was postulated that adding moisture actually reduced the process efficiency because of the energy required to heat the additional water. 

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