Transmitter antenna

Working with an NMR spectrometer is slightly more difficult than, for instance, with an electron microprobe. As the NMR frequencies are all in the radio frequency range, NMR spectrometers are computer operated radio transmitting and receiving systems controlled by a computer. A receiver and transmitter antenna surrounds the sample, which is located in the cavity of a super-conducting cryomagnet. 

HaUas,Joel R. Basic Radio Understanding the Key Building Blocks. Newington, Conn. American Radio Relay League, 2005. An introduction to radio that discusses its components receivers, transmitters, antennae, propagation, and their applications to telecommimi-cations, radio navigation, and radio location. 

Figure 1 Representation of a bilateral pacing system. Note the following components—transmitter, antenna, receiver, and electrode. Source From Avery Biomedical Devices.

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... 

Multicavity filters. Multicavity Fabry-Perot filters are used to make very narrow transmission filters. A simple Fabry-Perot cavity (see Ch. 2) consists of a halfwave layer surrounded by two reflectors of typically 10 layers each. Figure 4 shows three transmission profiles obtained with one, two or three cavity filters. The three cavity HL) 5HH(LH) 5) " 3 filter has a 1.2 nm bandwidth. It has 60 layers. Note that the three-peak top of the transmittance. Each cavity has to be well adapted to the following one if not the resulting transmittance can be very poor. Such cavities are broadly used in telecoms in between arrays of antennas for cell phones. 

Fig. 14.4 Apparatus for electrodeless photochemical irradiation. A. antenna, B. transmitter, C-j. capacitor, C2. variable capacitor,...

Classical pulse radar emits high power (Pr) short electromagnetic pulses using a directional transmitting antenna of gain Gt The power density at the target at distance R from the transmitter is equal to [44]... 

Using the bi-static concept can reduce all of the above mentioned problems. The spatial separation of the transmitter and receiver antennas leads to significant attenuation of the direct path signal. In addition, the near-far target problem is reduced, while the target signal can be... 

The superposition principle allows us to assume just a single scatterer in the view of the radar. The transmitted signal hits this scatterer whose distance (we measure distance and time in the same units) from the (collocated) transmitter and receiver is r. Assume that the scatterer is stationary. The return signal will be a delayed version of the original, delayed by the total round trip time from the radar to the scatterer. Specifically the signal voltage at the antenna of the receiver is... 

WAP. The WAP provides the wireless data communication service. It usually consists of a housing (which is constructed from plastic or metal depending on the environment it will be used in) containing a circuit board, flash memory that holds software, one of two external ports to connect to existing wired networks, a wireless radio transmitter/receiver, and one or more antenna connections. Typically, the WAP requires a one-time user configuration to allow the device to interact with the local area network (LAN). This configuration is usually done via a Web-driven software application which is accessed via a computer. 

Second, the superconductively charged harmine complex within the stone will act as its transmitter and energy source. It is interesting to note that the same energy that sustains the antenna circuits in superconductivity will sustain the whole of the device. 

A CW NMR spectrometer (Figure 3.14) consists of a control console, magnet (typically electromagnets or permanent magnets are used), and two orthogonal coils (transmitter and sweep coils) of wire that serve as antennas for rf radiation. One coil is attached to an rf transmitter and the other coil is the rf amplifier (pickup) coil and is attached to the detection electronics. 

Fig. 6.171(a) Mobile station (e.g. on a locomotive) containing a transmitter module, a receiver module and an antenna adaption module. 

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