Science > Physics > Communication > Amplitude Modulation The first amplitude modulated signal was transmitted in 1901 by a Canadian engineer named Reginald Fessenden. He used a continuous spark transmission and placed a carbon microphone in the antenna lead. This transmission was very crude, signals were audible over a distance of a few hundred metres. The […]
Science > Physics > Communication > Modulation Before the concept of the modulation, the signal used to be sent in form continuous wave with periodic interruption as in morse code. To code, send and decode such message high expertise was required. The direct current is not suitable for transmitting the data because of its steady nature. […]
Science > Physics > Communication > Optical Fibre: Principle and Working The optical fibre is a device which works on the principle of total internal reflection by which light signals can be transmitted from one place to another with a negligible loss of energy. Characteristics of Optical Fibre: It has a large bandwidth. The optical […]
Science > Physics > Communication > Communication Channel: Line Line Communication: Space communication is unguided communication. In this communication channel, there is no physical contact between the transmitting and the receiving antenna. The transmitted signal spreads in all directions. This results in the attenuation of the signal. To avoid the attenuation we use line communication. […]
Science > Physics > Communication > Satellite Communication Radio Communication uses ground wave, skywave, and space wave propagation. Ground wave and space wave communication are restricted to small distances, whereas skywave propagation uses frequencies ranging from 3 MHz to 30 MHz. Very high frequency (> 30 MHz) and microwave communication over long distances use a Satellite. […]
Science > Physics > Communication > Coverage Area of Antenna An antenna or aerial is a system of elevated conductors which couples the transmitter or receiver to the communication channel. Thus it is required at both ends i.e. transmitter end and receiver end. The same antenna can be used for transmitting and receiving functions. Expression […]
Science > Biology > Digestion and absorption in Human > Buccal cavity – Teeth In this article we shall study, the characteristics of teeth (dentition), different types of teeth and the structure of the tooth. The teeth are the strongest, hardest and rigid substances in the human body specialized for the biting and grinding of […]
Science > Physics > Communication > Communication Channel: Atmosphere A communication channel is a link connecting a transmitter and a receiver. It is the physical medium which carries the signal from the transmitter to the receiver ideally without any noise or distortion. The atmosphere, optical fibres, parallel wires, coaxial cables, etc. are used as communication […]
Science > Physics > Communication > Terminology of Communication System In this article, we are going to study the terms used in the communication system and the concept of the bandwidth of a signal. Transducer: Any device that converts one form of energy into another can be termed as a transducer. Example: A microphone is […]
Science > Physics > Communication > Communication System Communication is the process of exchange of information between two entities. It involves sending, receiving and processing information. Thus there is a transmission of information from a source at one place to a receiver located at another place. The communication system is a device or setup used […]