Electromagnetic Waves

Electromagnetic Waves

Introduction

Communication has come a long way from when we relied on smoke signals, lighthouses and men that rode on horses through the night. Advances in technology have utilized naturally occurring phenomenon, much to our advantage, and made it possible to communicate with someone on the other side of the world without raising our voice beyond a whisper. This paper discusses radio waves and lens beams. It discusses hertz and the concept of refraction. It then goes on to discuss refraction and radio stations.

Radio Waves vs. Lens Beams

A receiver and transmitter are used for the effective interception and propagation of radio waves. A radio wave is a means, or usually termed as a carrier, for signals that carry information. This specific information may be direct, in terms of periodic interruptions that may resemble Morse code in some manners or could be superimposed by a technique called modulation. In modulation, the information of importance is part of sidebands. Side bands are an inherent part of frequencies that are added to the carrier wave. Carriers do not hold any information and are often discarded after proper reception at the receiving end of communication process. The two most common and prevalent forms of modulation are frequency modulation, FM, or amplitude modulation, AM. Frequency modulation is more adept at minimizing noise as compared to amplitude modulation. It also provides greater fidelity (Sterling, 2009, pp. 1288-90). Amplitude modulation is an older technique and is known for its larger are coverage as compared to frequency modulation. Both amplitude and frequency modulation techniques are forms of analog communication. They are electrical representations of sound, done so by varying frequency and amplitudes than superimposing this signal on to a high frequency signal (Rutledge, 1999, p. 310).

Radio waves are most commonly used to transmit sound and images for radio sets and television sets. For the radio, sounds are converted into electrical signals using a microphone, a transducer, and video recording is used to capture images. Once the signal has been captured, it is proportionately amplified and then used to modulate a carrier. Carrier waves are created using an oscillator circuit, inbuilt in the transmission system. Once modulated, the modulated signal is amplified further before it is finally fed to an antenna. The antenna serves as the translator between two mediums. It effectively converts the electrical signal to an electromagnetic form, allowing it to radiate in free space. These ways radiate at the speed of light and usually travel as per the line of sight. However, waves are also capable of traveling further by bouncing them off the Ionosphere; another example of refraction(Rutledge, 1999, p. 310).

At the receiving end, similar antennas intercept radiated signals and convert them from their electromagnetic form to an electrical signal. This signal is fed to the receiver. Super heterodyne receivers are the most commonly found type of circuits for radio frequency amplification and frequency selection. They are also one of the most efficient. In a super heterodyne receiver, incoming signals are mixed with ...