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Basic Electronics

Analog and Digital Electronics: Differences

This text explains, compares and shows the main differences between analog and digital electronics. On the one hand, analog electronics use continuous signals, where any value is possible. However, digital electronics are based on binary signals, where only two possible states are allowed. The contrast between the two worlds is obvious, and is described in more depth below.

1. Analog Electronics

An analog signal, be it a voltage or a current, is always bounded. In other words, an analog signal always has a maximum value, which we will call Vmax, and a minimum value, which we will call Vmin.

The key is that the variation interval between both margins, Vmax and Vmin, is always continuous. That is, any value within the range is possible. This is equivalent to stating that an analog signal can have infinite values.

Let’s see it with an example. The signal in the following image represents a voltage with Vmax = 3 and Vmin = -0.5. Within that range there are infinite values ​​through which the signal passes. For example: 0, 0’1, 1’001, etc

Analog vs Digital Electronics: Analog Signal.
Analog Signal.

2. Digital Electronics

In contrast to analog signaling, a digital signal has the following two main differences. On the one hand, the digital signal is divided into intervals called bits. On the other hand, there are only two possible states or values ​​for each bit: ‘1’ or ‘0’.

The following image shows an example of a transmitted digital signal with a value of “10110010”:

Analog vs Digital Electronics: Digital Signal.
Digital Signal.

3. Analog Electronics vs Digital Electronics

In line with the differences between analog and digital signals, the main advantages and disadvantages are also derived.

3.1 Noise Tolerance

If an analog signal becomes contaminated with noise, the original signal may be unrecoverable.

Instead, let’s see what happens with a noisy digital signal. The same signal shown in section 2, “10110010”, is illustrated below, affected by noise, interference and distortion:

Analog vs Digital Electronics: Distorted Digital Signal.
Distorted Digital Signal.

The original signal is perfectly recoverable. To do this, it is only necessary to compare with the threshold (red line) at each sampling instant.

Therefore, it can be concluded that a digital signal is more robust and noise tolerant than an analog signal.

3.2 Suitability to Store Information.

Derived from the previous point, it can also be concluded that a digital signal is more appropriate for storing information. Indeed, any type of corruption of a signal stored in analog form results in an immediate loss of quality. On the other hand, in digital information, corruption has no effect as long as it is possible to continue discriminating the original values.

For example, VHS video storage systems suffered from permanent quality losses due to multiple views and the passage of time. In contrast, a video stored in DVD format is much more durable and resistant to corruption, without suffering any loss of viewing quality.

4. Analog and Digital Signals Summary

ANALOG SIGNAL

Continuous Time

Continuous Value

Noise Sensitive

Not optimal for storage

DIGITAL SIGNAL

Divided into Intervals, bits

Binary

Noise Tolerant

Optimal for storing information

5. Further Reading on Analog and Digital Electronics

This text has explained in a basic way the differences between analog and digital electronics. In this sense, the text has emphasized the advantages of a digital signal over an analog one. These advantages have been decisive in imposing digital standards and digitization as the basis for problem solving.

To delve a little deeper into the differences between analog and digital electronics, the following readings are recommended, which are part of our electronics summary: