Difference Between Attenuation and Distortion

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

1. 1. Comparison Chart
   2. Definition
   3. Key Differences
   4. Conclusion

Comparison Chart

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.

Conclusion

The attenuation results in the reduction of the signal strength while distortion alters the original signal.