Analogue signals

An analogue signal uses some property of the medium to convey the signal’s information.
For example, an aneroid barometer uses angular position as the signal to convey pressure
information. Electrically, the property most commonly used is voltage followed closely
by frequency, current, and charge.Any information may be conveyed by an analogue signal, often such a signal is a measured response to changes in physical phenomena, such as sound, light, temperature, position, or pressure, and is achieved using a transducer.

They can take any value from a given range, and each unique signal value represents
different information. Simply put, any change in the signal is meaningful, and each level
of the signal represents a different and unique level of the phenomenon that it represents.
For example, suppose the signal is being used to represent temperature, with one Volt
representing one degree Celsius. In such a system 10 Volts would represent 10 degrees,
and 10.1 Volts would represent 10.1 degrees.


A similar digital circuit may only represent temperature to the nearest degree, so that 10.0 Volts and 10.1 Volts would both represent exactly 10 degrees. In an analogue sound recording, the variation in pressure of a sound striking a microphone creates a corresponding variation in the current passing through it or voltage across it. An increase in the volume or amplitude of the sound causes the fluctuation of the current or voltage to increase proportionally while keeping the same waveform or shape and electrical analogue.


Disadvantage is The primary disadvantage of analogue signalling is that any system has noise, that is random disturbances or variations in it. As the signal is copied and re-copied, or
transmitted over long distances, these random variations become dominant and lead to
signal degradation. Electrically these losses are lessened by shielding, good connections,
and several cable types such as coax and twisted pair and using low noise amplifiers. The effects of random noise can make signal loss and distortion impossible to recover,
since amplifying the signal to recover attenuated parts of the signal often generates more
noise and amplifies the noise as well.