As we have seen in the preceding sections, the connection between transmitter an the receiver is established through communication channel. We have seen that communication can take place through wirelines, wireless or fibre optic channels. other media such as optical disks, magnetic tapes and disks etc. can also be called as communication channel, because they
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Fig shows the basic elements of a digital communication system. The source and the destination are the two physically separate points. When the signal travels in the communication channel, noise interferes with it. Because of this interference, the smeared or disturbed version of the input signal is received at the receiver. Therefore the signal received
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We know that electromagnetic waves have two fields. One field is electric field and other is magnetic at 90°. The direction of propagation of those waves is perpendicular to both electric and magnetic fields. The electromagnetic waves travel at the speed of light (3 x 108m/sec). They can travel on electric conductors, in air, in
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Before discussing about modulation and demodulation directly, we will consider an interesting example first. Let us consider that you want to send some “parcel” from Pune to Nasik. It is obvious that the parcel cannot move from Pune to Nasik on its own. What all you need to do is, to contact some courier company.
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From the examples of communication discussed so far, now we can prepare the model of basic communication system. We know that for any communication to take place, three things are essential. They are, Transmitter (talker) Receiver (listener) and Channel or transmission medium. The above three things are present in any communication system. Whenever two people
Basic Communication System – Communication Engineering Read More »
What is Communication ? Communication is the process of establishing connection (or link) between two points for information exchange. In our day to day life we come across many ways of communicate. For communication to take place, three essential things must be present. Sender or Transmitter : It sends information. For example TV transmitting station
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The thermistor is a semiconductor device that has a negative temperature coefficient of resistance. Thermistors are non-metallic resistors, that is, semiconductors of ceramic materials. Basic Principle : The basic principle involved in thermistor is, when it is subjected to a temperature change, the resistance of the thermistor changes. This change in resistance will be the
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The most common method of temperature measurement uses the thermocouples. It is based on seeback effect. The thermocouple temperature measurement is based on creation of an electromotive force (e.m.f). Basic Principle : The basic principle of thermocouple is when two dissimilar metals are joined together an e.m.f will exist between the two points A and
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The pressure thermometer temperature measurement is based on fluid expansion. Fluid expansion thermometer represent one of the most economical, versatile, and widely used devices for industrial temperature measurement applications. Basic principle : The basic principle in pressure thermometers are when liquids, gases or vapours are heated, they will expand, when they are cooled, it will
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This method refers to the identification of the temperature of a surface with the colour of the radiation emitted. The optical pyrometer compares the brightness of the image produced by the temperature source with that of a reference temperature lamp. The optical pyrometer has an eyepiece at one end and an objective lens on the
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