There are two types of signals – analog and digital. Both of them have specific use cases and advantages or disadvantages. Therefore, this article will provide you with the main differences and the advantages, as well as the disadvantages, of both types.
The differences between analog and digital
| Analog | Digital |
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Because digital uses ones and zeros instead of continuous values like analog does, it is slightly less accurate but therefore more reliable and resistant to interference as small varies in the voltage don’t change a zero to a one or the other way around. Additionally, digital signals have got a higher latency compared to analog signals. However, digital signals are sent and received as binary bits hence using less power.
How analog signals work
Analog signals work with variations in the voltage with which the signal is sent. Because of the voltage changes, an analog signal has got the form of a wave. This wave has got different essential properties:
- amplitude
- frequency
- wavelength
- phase
Amplitude
The amplitude measures the strength of the signal (voltage) at any point in time. For example, the amplitude of the image above varies between 0.65V and -0.65V.
Frequency
The frequency measures how many times in a second the amplitude cycles from 0 to the highest amplitude, then to the lowest amplitude, and up to 0 again. The frequency is specified in the unit Hz (Hertz). For example, the signal of the image above has got a frequency of 1Hz.
Wavelength
The wavelength measures two corresponding points of a wave’s cycle. It is usually specified in meters or feet and is inversely proportional to the frequency.
higher frequency = lower wavelength
lower frequency = higher wavelength
We can calculate the wavelength with the following formula:
Wavelength (m) = Wave velocity (m/s) / Frequency (Hz)
Assuming the wave velocity of the wave above is the speed of light in the air (about 299,702,547m/s), we get a wavelength of about 299,702,547.
Wavelength (m) ≈ 299,702,547(m/s) / 1Hz = 299,702,547m
Phase
A phase is the progress of a wave in relationship to a fixed point and time. A phase is measured in degrees. Different phases allow us to transmit a signal with the same amplitude and frequency multiple times. For instance, to transmit two signals with the same amplitude and frequency, we could start one wave at its lowest amplitude and the other one at its highest amplitude.
By looking at all these waves of analog signals, it becomes very clear why analog signals are so vulnerable to interference. Simply, only small variations in the voltage or other properties can lead to a completely different wave/signal.
How digital signals work
Other than analog signals, digital signals do not have continuous and infinite values. They only rely on the two binary digits – 1 and 0 (either on or off). Compared to analog, the voltage/strength of the signal doesn’t matter as much hence digital signals aren’t as vulnerable to interference.
Another advantage of digital signals is that computers don’t have to convert them into binary like they have to do with analog signals.
Summary
In conclusion, analog signals are more accurate and have less latency compared to digital signals. However, digital is more reliable and less vulnerable to interference and needs less power than analog transmission.
Analog is transmitted via different voltage values (amplitudes) whereas digital is transmitted as binary bits.
Thanks for reading!
