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GNSS Signals and Range Determination
Published in Basudeb Bhatta, Global Navigation Satellite Systems, 2021
A radio transmitter essentially consists of: (1) a power supply to furnish direct current, (2) an oscillator to convert direct current into radio-frequency oscillations (the carrier wave), (3) a device to control the generated signal, and (4) an amplifier to increase the output of the oscillator (Bowditch 1995). When a radio wave passes a conductor, a current is induced in the conductor. A radio receiver is a device which senses the power thus generated in an antenna and transforms it into a usable form. It is able to select signals of a single frequency (or a narrow band of frequencies) from among the many which may reach the receiving antenna. The receiver is able to demodulate the signal and provide adequate amplification. The output of a receiver may be presented audibly by earphones or loudspeaker or visually on a dial, cathode-ray tube, counter, or other display. Thus, the useful reception of radio signals requires three components: (1) an antenna, (2) a receiver, and (3) a display unit.
Flow
Published in Martin Novák, Introduction to Sensors for Electrical and Mechanical Engineers, 2020
The principle of ultrasonic flowmeters is shown in figure 12.16. They are equipped with ultrasonic transmitters and receivers. The transmitters send signals, and the signals are received by the receivers. When the ultrasonic signal travels upstream it is being accelerated by the flow. If it travels downstream it is being slowed down. The time difference between the upstream and downstream timing is a function of flow velocity. The sensor features at least one pair of receiver and transmitter. With more pairs the flow profile can be measured more accurately.
Coherent Systems
Published in Jerry D. Gibson, The Communications Handbook, 2018
Basic construction of the coherent optical fiber communication system is shown in Fig. 53.1. Amplitude, frequency, or phase of an optical carrier is modulated at a transmitter directly or by using a modulator. The electric field of the optical signal is expressed as
Energy efficient optimal hop transmission using minimum power least cost algorithm in cooperative routing for wireless sensor network
Published in Automatika, 2023
Immanuvel Arokia James K., Manjula P., Guga Priya G., Karthikeyan A.
Radio receivers and transmitters, as a rule, require antennas, keeping in mind the end goal of coupling electrical association with the electromagnetic field. Radio waves are generally electromagnetic waves that help motions through space or air at the speed of light with practically no transmission misfortune. Radio transmitters and receivers are utilised to pass on signals in broadcast (audio) radio, TV, portable Wi-Fi (WLAN) data networks, and remote control gadgets, among numerous others. Reception apparatuses are typically omnidirectional. They generally emanate energy similarly every which way, or directionally, where energy transmits more along one bearing than others. It's physically difficult to get a totally uniform omnidirectional antenna. Reception apparatuses, as a rule, send little energy upward or downward; however, they for the most part have a uniform radiation design in the horizontal plane [7].
Requirements and challenges for infusion of SHM systems within Digital Twin platforms
Published in Structure and Infrastructure Engineering, 2023
Rolando Chacón, Joan R. Casas, Carlos Ramonell, Hector Posada, Irina Stipanovic, Sandra Škarić
Another technique is RADAR. The acronym reads Radio Detection and Ranging systems. By means of a transmitter, the radio produces an electromagnetic signal that is then propagated into the space by means of antenna. When this signal strikes an object, it gets reflected back. The reflected signal is known to be the echo signal. The receiver then processes the echoed signal. For finding the range of the object, the system uses the time taken by the signal to get reflected. For the target location, an angle is calculated from the direction of the echo signal to the direction where the antenna is pointing. For moving objects, the Doppler Effect is used to calculate the speed and range of such object.