Attenuation and distortion are the types of impairment occur in the signal, in other words, these are the undesired effects on the signals. The difference between attenuation and distortion lies in the fact that in attenuation the signal losses some part of energy where the amplitude of the signal may decrease. On the other hand, distortion is the change in the waveform of the signal due to noise.
Transmission lines experience three significant issues due to imperfect transmission media that are attenuation, distortion and noise. The weakening of the strength of a signal makes it undetectable at the receiver’s end, that is attenuation. The signal must be sufficiently high for being detected at the destination even in the presence of the noise.
Additionally, attenuation of different frequency components is not the same, some frequencies are highly attenuated, and some suffer low attenuation. This reliance of the attenuation of the channel on the frequency of the signal rises the distortion.
Content: Attenuation Vs Distortion
|Basis for comparison||Attenuation||Distortion|
|Shape of waveform||Does not change||Altered|
|Obliteration of the effects||Easily removed||Harder|
|Relationship||Reduction in amplitude, and cause of distortion.||Attenuation occurs in different amounts at different parts of the signal.|
Definition of Attenuation
When a signal travels in space through a medium, it loses some part of its energy. Similarly, a wire allowing the electric current (electrical signals) to flow through it gets heated due to the resistance produced by the medium. In the above-given example, the energy of the electrical signal is dissipated in the form of heat. The diminution of the power or energy is known as attenuation.
This loss is measured in decibels per kilometre. Attenuation largely depends on the frequency, to understand this let’s take an example of a complex signal such as a series of Fourier elements. Every element is propagated at a distinct speed; as a result, the Fourier spectrum received at the receivers end is different. It increases exponentially according to the distance travelled.
Attenuation is inverse of amplification, the extensive attenuation in signal makes it unintelligible. That is the reason for the use of repeaters at fixed intervals.
Definition of Distortion
Distortion is different from attenuation, this type of impairment in signal alters the shape and form of the signal. It eventuates in a composite signal constructed by distinct frequencies. Each signal element has its associated propagation speed and delays at the time of travelling through a medium; consequently, the arriving time of the signals may change.
In the example given in attenuation, the Fourier elements propagating at a different pace, this difference in speed result in distortion of the signal obtained at the other end. The distortion occurs due to the properties of the medium. There are several types of distortions such as amplitude, harmonic and phase distortion.
Key Differences Between Attenuation and Distortion
- Any loss in the strength on the signal because of resistance of the medium is called as attenuation. On the other hand, distortion is any alteration of the original signal induced by the attenuation, noise or any other type of interference.
- Attenuation does not change the waveform of the signal while distortion does change it.
- Overcoming from the effects of the attenuation is easy. As against, distortion effects are harder to remove.
- When the level of amplitude reduces over the specific amount in the signal, it is known as attenuation. On the contrary, distortion is the attenuation happening at the different amount and distinct parts of the signal.
The attenuation results in the reduction of the signal strength while distortion alters the original signal.
Wow , I love the detailed explanation… Very helpful.
Please, can I have a book(s) on communication systems.
This is very helpful