In this series of digital electronics, also known as digital logic or digital logic and designing. In this tutorial of digital electronics, we will first see what a signal is, then number systems and codes under that we are going to cover, the basic number systems like binary, decimal, and hexadecimal, and conversions from one number system to another number system.

We will discuss more in the coming tutorials, so let first start with an elementary signal.

### What is the signal?

The signal is a function that represents the variation of a physical parameter. The parameter is the independent quantity, and it is generally time or distance. In electrical and electronics, usually, the signal is the variation of electrical component generally current (I) or voltage (V) over time (T).

The most important point you must know is if the current or the voltage remains the same for a different time, then it is not a signal.

If the current is the same for the different time, then it is direct current, it is not a signal. We can say the small change in the current is equal to zero.

The **transducers **are the device that used to convert the non-electrical signal to an electrical signal.

Let’s take an example you are singing a song on the mic. The mice will convert your voice into the electrical signal through the vibration, and that electrical pulses are amplified. Once it is amplified and send to the speaker and hence through a sound system, we can hear the voice.

let’s move to the next type of signal that is the **discrete-time signal**, so let’s study what is a discrete-time signal because it is important to understand this signal before we move to the digital signals.

#### What is a discrete-time signal?

A discrete-time signal is a signal which is defined for the discrete interval of time is known as a discrete-time signal.

**Analog signal** is the continuous variation of information such as current or voltage.

For example, a current is varying in the form of a sin curve.

NoteAll real-life signals are analog.

**Digital signal** is the follow of information in discrete form.

For example, a digital signal follows a binary system that can have two values, either 0 or 1 means low level or high level.

A Digital signal is used in the communication process to minimize the effect of noise, i.e., unwanted signal.

We will discuss more in the upcoming following tutorials, like what is the number system and much more.