Analogue vs Digital

Analogue VS Digital

Introduction:
In this blog post, I will be explaining what the analogue is in general as well as digital and what makes them different from each other. Furthermore, as each is different I will identify its limitations where relevant and provide examples of each example of signals.

Analogue:
Analogue in general is the form of data humans interpret, such as sound and music. For example, if you record someone speaking or singing, usually a device of some sort such as an oscilloscope will display a very natural sine waveform, (see figure 1). Furthermore, the cables are very sensitive to high currents such as from AC (alternating current) and therefore uses DC (direct current) for the device’s components to not over heat. However, AC has a high voltage to keep it accurate.

In more depth within the analogue’s waveforms, there are many different types which include:

• Amplitude: The power of a wave; from the peak (maximum disturbance) to the line where it started from (undisturbed disturbance). This defines the loudness which corresponds to it; meaning that as the sound gets louder, so will the amplitude (height). An example would be a loud thump and this will result in a very tall amplitude when it is shown.
• Frequency: Is how frequent the wave pattern repeats itself within a second from point of a wave to another in a repetition. An example is a very fast paced music which will result in a high frequency rate as more waves are compressed within the second; this means a lot of sound is being made. Moreover, different types of waves can also determine the frequency used.
• Wavelength: A wavelength is a single point of a wave (cycle) to the next exact point on the other. A wavelength can sometimes be useful for measuring how long a waveform is, hence the name given.
• Cycle: Is a single point of a wave (wavelength) to the next exact point on the other. Cycles can be useful for determining whether the signal is a low frequency or if it is a high frequency – “A low frequency signal has a small number of cycles per second; a higher frequency signal can have billions of cycles per second”, (Anderson et al, 2011).
• Period: Carries out the same properties and measuring method of a cycle and or wavelength, however the only difference is that the two specific points can be anywhere on the analogue wave. This can be a way of sampling a specific range.

With analogue waves, the accuracy increases greatly but the limitations of these results in larger file size. This makes it inconvenient and would be difficult to distribute music for example. Another limitation of analogue is that it is very sensitive to sound such as background noises, picking up unnecessary sounds that may potentially increase the file size – this distorts it.

Figure 1: Analogue Waveforms

Digital:

However, on the other hand the limitations can be solved by converting analogue waves to digital format. To do this, it requires the excessive use of sampling rates – these are essentially points placed on an analogue wave which allows a digital reconstruction for the devices to store in (see figure 2), an example would be the .MP3 file stored in an MP3 player after conversion.

Figure 2: Analogue Conversion Digital

Figure 3: Analogue Sampling

Consequently, the limitations of digital is that the accuracy of the analogue waves are lost during conversion, removing the ability for our human ears to be able to hear as precise, thus the excessive use of sampling would also increase the file size overall too. To combat this, filters such as ‘Flac’ can be applied to the digital reconstruction to make it similar to the actual analogue wave when played back, this is because it is provides lossless for the quality.

Devices such as a computer can read binary numbers made up of 1’s and 0’s and that is what sampling does, by assigning each sample a code, (see figure 3). Moreover, it is necessary for analogue to be encoded digitally for it to be stored in devices such as a smartphone. Another primary usage of digital is that it can be easily manipulated with the help of software’s like Audacity where the frequency and amplitude can be altered etc. Then lastly, for example when a music file is stored digitally on a MP3 player, when it plays back it will convert it back to analogue with little quality lost.

Harvard Referencing: (In order of reference)
- Anderson, K. Atkinson-Beaumont, D.Kaye, A. Lawson, J. McGill, R. Phillips, J and Richardson, D. 2011. Information Technology Level 3 Book 1 BTEC National. Harlow: Pearson Education Limited.
- Figure 1: Chan, D. 2015. Analogue Waveforms. [Accessed 26 January 2015].
- Figure 2: streaming.wisconsin, n.d. Analogue Wave. [Online] Available at: <http://streaming.wisconsin.edu/images/audio_editing_SF_images/sf00sample.gif> [Accessed 26 January 2015].
- Figure 3: screaminfx, n.d Analogue Verses Digital. [Online] Available at: <http://screaminfx.com/images/tech-images/what-is-analog-verse-digital-explanation.jpg> [Accessed 26 January 2015].

Bibliography: (In alphabetical order)
- bbc, 2014. Amplitude, Wavelength and Frequency. [Online] Available at: <http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/radiation/anintroductiontowavesrev2.shtml> [Accessed 26 January 2015].
- webopedia, 2015. Digital. [Online] Available at: <http://www.webopedia.com/TERM/D/digital.html> [Accessed 26 January 2015].