A signal is an electric current that is used to transmit data among different electronic devices. The data is fed into the signal through modulation processes – which can be either digital or analog. Although being continuous in nature, Analog signals do not remain constant within an interval. On the other hand, digital signals are discrete and non-continuous in nature.
The primary difference between these signals is that square waves can be used to depict a digital signal, but sine waves are used to illustrate analog signals. Let us look at the other characteristics that separate the analog from digital signals.
What is Analog Signal?
An analog signal is a continuous signal that is time-varying in nature. This signal is further classified into two types – composite and simple signals. Simple signals, being a sine wave, cannot be broken down into other signals. But, composite signals are decomposable into multiple sine waves.
Furthermore, analog signals can be defined by two ways – using amplitude and time period or using frequency and phase. To analyse the greatest height of the signal, amplitude is used. Frequency measures the rate of change of the analog signal. Phase specifies the position of the signal with respect to time zero. The distance between two peaks of a sine wave or one complete sine wave cycle is called one time period.
Analog signals are not immune towards noise and hence its transmission quality can be hampered if it is exposed to noise.
What is Digital Signal?
Digital signals are also responsible for carrying information but are not continuous like analog signals. The signal carries data in binary form, where the information is represented in bits. Furthermore, these type of signals can be broken down into sine waves called harmonics.
Digital signals can be described using a bit rate or a bit interval. The time needed for transferring a single bit is defined by bit interval. The frequency of this bit interval is defined using bit rate.
Unlike analog signals, digital signals are noise-resistant and do not face any distortion. So they are more reliable during transmission of data.
Now that we have a clear idea about the fundamentals of the two signals, let us compare them to find out which one is more efficient.
Analog vs Digital Signals
In Analog signals, data or information is transferred in wave form. The medium of transmission can be wired or wireless.
In case of a digital signal, data is transferred in binary bits of 0 and 1. The medium of transmission is wired.
Analog signals require less bandwidth and signal processing can be done in real-time. Digital signals require more bandwidth.
For a range of uses, analog signals are less adjustable as compared to digital signals, which can be adjusted accordingly.
Analog signals are more prone towards distortion so while sending data noise can cause interruption and reduce the signal quality.
On the other hand, digital signals are less prone to distortions so the transmission quality is not affected.
Analog signals are recorded on a phonograph record or on a magnetic tape as field strength fluctuation. The process preserves the original signal.
While in the case of digital signals, they are recorded on a compact disk, digital recorders, magnetic tape or an optical disk. The sample signals are conserved in the process.
Analog signals are used along with analog devices such as telephone handsets, radios, thermometers, megaphones, and cassettes.
Digital signals are used along with devices such as laptops, mobile phones, PDAs and desktop computers.
Digital signals are encrypted and are more secure. However, analog signals are not encrypted they have less security.
Analog signals are found in devices like a thermometer that are of lower cost as compared to digital signals found in computers and mobiles that are costlier.
Impedance is the measure of the opposition a direct or alternating current faces when it is passed through a circuit or a conductor component. Analog signals have low impedance whereas digital signals have higher impedance.
Advantages of Digital Signal Over Analog Signal
The advantages of digital signals as compared to analog signals are:
- Digital circuits are easier to design than analog signals
- Distortion, interference and noise do not affect these signals as compared to analog signals
- Configuration of digital signals is easier than analog
- The possibility of errors in these signals are less as error-detecting algorithms are used
- They can be stored and retrieved easily than analog signals
- Problems like signal jamming are avoided using speared spectrum technique
- Implementing hardware in digital circuits is more flexible
- Enables multi-directional transmission over long distances
Digital and analog components can be seen in digital circuits although digital signals are taking over analog signals. It has been observed that digital signals are better than analog signals in terms of distortion and interruptions, making it far better than analog signals. Other factors that make it better than analog signals are easier circuit design, security through encryption and configuration.