Communication system transmit information from one place to another place by means of electric energy. This paper describes the analysis and design of electronic circuits used in radio frequency communication systems covering the frequency range up through several hundred megahertz the actual frequency lit depends upon whether the circuit is realized with decree components or as an integrated circuit.
The electromagnetic waves that leave transmitting antenna arrive at the receiving antenna in one of the many waves. These include ground waves, sky waves, space waves, and via satellites. Ground waves travel along the ground and follow the terrain. Radio wave propagation is concerned with how radio signal generated by a transmitter moves to receiver located some distance away. As the portion of electromagnetic frequency spectrum that is used for broadband wireless communication extends from 300 MHz to 300 GHz. The frequency range covers over wavelength from 1m to 1mm. In these frequencies bands, radio waves are transmitted as space waves. That is, neither ground nor sky waves are used at these frequencies.
The simplest radio –propagation environmental is free space with no atmosphere and no solid object along the path between the transmitter and receiver. Such an environmental permits radio signals to travel in a line-of-sight manner and be received as direct waves. Unfortunately, this model is oversimplification of practical propagation environments where the radiated wave comes in contact with solid objects that produce changes in its amplitude, phase, and direction of propagation. Even in the absence of solid objects, the radio signals strength decreases as the probation distance increases. The medium over which the radio wave tra...
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...ts. This means that the network management system must be such that will periodically monitor the RSSI for each mote. When the RSSI is below a predefined threshold, it should be possible to remotely reconfigure the affected mote so that it can access the network via the second access point that it can see.
The task of managing the network is complicated by many factors, which include the different networking technologies, heterogeneous systems from a myriad of vendors; and a number of distributed applications, some of which have vendor specific requirements. Added to this is the fact that many new network applications are imposing great QoS and security demands on the network. The task of configuring the network to meet the end-to-end QoS and security requirement of each application is a tedious one that cannot be handled by traditional network management systems.
Radio systems must have transmitter to modulate some property of the energy produced to impress a signal on it. To using amplitude modulation or angle modulation ,which can be frequency modulation or phase modulation. Radio systems have antenna to convert
The precedence of RFID is that it does not require direct contact or line-of-sight scanning. An RFID system consists of three components: an antenna and transceiver (often combined into one reader) and a transponder (the tag). The antenna uses radio frequency waves to transmit a signal that activates the transponder. When activated, the tag transmits data back to the antenna. The data is used to notify a programmable logic controller that an action should occur. The action could be as simple as raising an access gate or as complicated as interfacing with a database to carry out a monetary transaction. Low-frequency RFID systems (30 KHz to 500 KHz) have short transmission ranges (generally less than six feet). High-frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer longer transmission ranges (more than 90 feet). In general, the higher the frequency, the more expensive the system. RFID is sometimes called dedicated short range communication (DSRC).
In basic terms, this is a flash of radio signals from the orbiting satellite to the ground station. The satellite and radio signals are affected by space weather. The effects of space weather on satellite communication can be put into three categories: effects on the satellite, effects on the station, and effects on the signal propagating through the Earth’s atmosphere (Kennewell). Space weather affecting the satellite depends on where the satellite is orbiting. Earlier it was mentioned that geomagnetic storms negatively affect high orbiting satellites. These satellites are vulnerable to highly charged particles that are emitted from the sun (Kennewell). Effects such as upsetting memory, dielectric charging, and radiation damage to components of the satellite. These effects can create glitches in the satellite, degrade the satellite, and in extreme cases it can destroy the satellite (Kennewell). On the other hand, low orbiting satellites do not have these effects. They are less susceptible to the charged particles damage. Although this is the case, the low orbiting satellites suffer decay when solar activity is increased (Kennewell). These are the space weather effects on the satellite. The ground station is also affected by the solar winds. The goal of the ground station is receive signals from the satellite and transmit commands and communications to the satellite
Radio Detection And Ranging (RADAR) “is a method of using radio waves to detect the existence of an object and then to find its position in relation to a known point, usually the site of the radar installation.” Radar technology can be used to detect the position, speed, and direction of the moving or stationary objects (“Pulse-modulated”). Radars, often used for “electromagnetic surveillance,” has various hardware and software parts that work together to produce an effective reading of the position and motion of the objects. The transmitter of the radar is used to initiate the process by amplifying the pulse signals. It has three parts: “a high powered amplifier (HPA) with a high-stability electron gun, waveform generator and timing, and an antenna” (Kolawole, 37). “The low energy signal, collected by the antenna, is brought through the circulator and the transmit...
The radio works because of sound waves being transmitted from one receptor to the next. Electrons moving through a wire create a magnetic field and when a second wire is placed next to the first the electrons are transmitted. The second wire is then able to turn the moving electrons into an electrical current which produces the same sound that created the moving electrons in the first wire (Gugliotta). Italian inventor, Gulielmo Marconi received the British patent for the radio in 1897. In 1901, Marconi discovered that radio wires did not have to be close to each other to work and that radio signals could be transmitted over very large distances. On December 13, 1901 Marconi successfully transmitted a radio wave 2,000 miles across the ocean from Poldhu, England to St. John’s, Newfoundland. U...
Electromagnetic waves are waves that can propagate even though there is no medium. A magnetic field that changes with time can generate an electric field that also changes with time, and an electric field that changes with time can also produce a magnetic field. If the process is continuous it will produce a magnetic field and electric field continuously. If these magnetic fields and electric fields simultaneously propagate (spread) in space in all directions then this is a symptom of the wave. Such a wave is called an electromagnetic wave because it consists of an electric field and a magnetic field that travels in space.
Radio-wave technology is one of the most important technologies used by man. It has forever changed the United States and the world, and will continue to do so in the future. Radio has been a communications medium, a recreational device, and many other things to us. When British physicist James Clerk Maxwell published his theory of electromagnetic waves in 1873, he probably never could have envisioned the sorts of things that would come of such a principle. His theory mainly had to do with light waves, but fifteen years later, a German physicist named Heinrich Hertz was able to electrically generate MaxwellÕs ÒraysÓ in his lab. The discovery of these amazing properties, the later invention of a working wireless radio, and the resulting technology have been instrumental to AmericaÕs move into the Information Age. The invention of radio is commonly credited to Guglielmo Marconi, who, starting in 1895, developed the first ÒwirelessÓ radio transmitter and receiver. Working at home with no support from his father, but plenty from his mother, Marconi improved upon the experiments and equipment of Hertz and others working on radio transmission. He created a better radio wave detector or cohere and connected it to an early type of antenna. With the help of his brothers and some of the neighborhood boys he was able to send wireless telegraph messages over short distances. By 1899 he had established a wireless communications link between England and France that had the ability to operate under any weather conditions. He had sent trans-Atlantic messages by late 1901, and later won the Nobel prize for physics in 1909. Radio works in a very complicated way, but hereÕs a more simple explanation than youÕll get from most books: Electromagnetic waves of different wavelengths are produced by the transmitter, and modulations within each wavelength are adjusted to carry ÒencodedÓ information. The receiver, tuned to read the frequency the transmitter is sending on, then takes the encoded information (carried within the wave modulations), and translates it back into the sensory input originally transmitted. Many of the men who pioneered radio had designs for it. Marconi saw it as the best communication system and envisioned instant world-wide communication through the air. David Sarnoff ( later the head of RCA and NBC) had a vision of Òa radio receiver in every homeÓ in 1916, although the real potential of radio wasnÕt realized until after World War I.
Analog communication employs continuous transmission of an electromagnetic wave form that varies in frequency and amplitude.
Nature of wave: It is an electromagnetic wave as it does not necessarily require a medium for p...
By the time the 20th century arrived, vacuum tubes were invented that could transmit weak electrical signals which led to the formation of electromagnetic waves that led to the invention of the radio broadcast system (750). These vacuum tubes were discovered to be able to transmit currents through solid material, which led to the creation of transistors in the 1960’s (750).
Radar can be traced back as far as 1832 when British physicist Michael Faraday suggested the existence of an electromagnetic field between certain objects from his scientific observations. Working from these ideas, British physicist James Clerk Maxwell predicted mathematically the existence and behavior of radio waves in 1873. In 1886, physicist Heinrich Hertz from Germany and Elihu Thomson from America confirmed the existence of radio waves with demonstrations showing examples of reflection, refraction, and direction finding of radio waves. By 1904, Christian Hulsmeyer, a German inventor, applied for a patent for a device that used radio waves in a collision-avoidance device for ships.
Networks in organisation are dynamic and complex entities which can be quite challenging to configure and manage. (Kim & Feamster 2013). These corporate networks consist of multiple routers, switches, firewalls, middleboxes and a particular advantage of network management is the ability to monitor the entire business network. As all the devices are interconnected with many event occurring simultaneously, problems with once device can eventually lead and spread throughout...
Network management planning and security planning involves identifying the best and most appropriate systems and hardware that the firm can use to better manage network and plan security systems. Therefore, the management required me to examine the best software and hardware systems in the market place that the company can adopt to enable it to manage the network and security. The management required me to advice on the implementation procedure of various plans that are going to be adopted. My responsibility also involved finding out or predicting the impact of the plan on the future operations. They required me to evaluate the challenges the company might face while adopting the changes in the network management plan and security plans.
RADIO WAVES: Radio waves are used exactly for what it says — radio. They are also the waves responsible for the signals cell phones and televisions receive. Objects in space, such as planets and comets, giant clouds of gas and dust, and stars and galaxies, emit radio waves.