Professor Sampler’s Notes: Disadvantages of Analog Systems

Topics Covered:

  • Definition of an analog device and system
  • The two major disadvantages of analog systems

Everything has a natural explanation. The moon is not a god, but a great rock, and the sun a hot rock – Anaxagoras

If everything around us is analog in nature, are there any disadvantages to analog systems?

Only the ones we engineer! Natural systems, like the eye and ear, have served us well. Or have they?

Take the game of Chinese whispers. Anyone who has tried to pass on a message through a chain of human beings will understand when I say:

1. The longer the message, the worse it gets at the end.
2. The more complicated the message, the worse it gets at the end.
3. The more the people playing, the worse it gets at the end.

This example highlights the single greatest weakness of an analog system, by which I mean a string of analog devices in a workflow. In the above example, each ear and vocal chord is an analog device, and the entire chain of humans makes an analog system. Every time a signal passes through an analog to analog converter (sound to microphone, light to film, bat to ball, etc) there is a loss in the signal, as discussed earlier. It is unavoidable. The best we can hope for is to keep our signals within certain limits so they remain useful. E.g., if we want to transmit the entire works of Shakespeare using purely analog systems, we’ll be pretty pleased if only a few letters get garbled at the receiving end. Shakespeare himself couldn’t have hoped for better.

For simple processes, analog systems are fine. Unfortunately, for complicated processes, where a great many analog devices have to be used in tandem, the losses just get multiplied and compounded.

Another great disadvantage that should be evident from the Chinese whispers example is that just because we can string a chain of ears does not mean each ear is the same. Even with the most careful manufacturing processes, no two analog devices are exactly similar. But we already know that, right? However, what happens when, in a workflow, people have to use analog devices not made by the same manufacturer, from materials that were sourced from different parts of the earth, with different designs (there is such a thing as intellectual property rights!) and different eyes and ears to judge the outputs of these devices? You get the picture. If you don’t, I’ll give it to you in one word: Chaos.

So, as creative people with nothing better to do, we decided to find a way to preserve a signal for the longest possible time, and use analog devices only when it is unavoidable.

How can this be done? Quite simple, really – we just changed the signals into discreet units that we know work. We use them everyday, at least the ones among us who have gone through preschool. Engineers call it code. When off duty, they call it language.

Takeaways:

  • Converting analog signals from one form to another always incurs losses.
  • No two analog devices are the same, and therefore duplicating a signal precisely is impossible.

Links for further study:

Next: Professor Sampler’s Notes: Digitization
Previous: Professor Sampler’s Notes: Wave-Particle Duality