A single valued function of one or more independent variables which contains some information is known as a signal.Basic Types of SignalsThere are several basic signals which play an important role in the study of signals and systems. These basic signals are the basic building blocks for the construction of ... Read More

What is Amplitude Scaling?The process of rescaling the amplitude of a signal, i.e., the amplitude of the signal is either amplified or attenuated, is known as amplitude scaling. In the amplitude scaling operation on signals, the shape of the resulting signal remains the as that of the original signal but ... Read More

Addition and Subtraction of Continuous-Time SignalsThe sum of two continuous time signals 𝑥1(𝑡) and 𝑥2(𝑡) can be obtained by adding their values at every instant of time. Likewise, the difference of two continuous time signals 𝑥1(𝑡) and 𝑥2(𝑡) can be obtained by subtracting the values of one signal (say 𝑥2(𝑡)) ... Read More

Even SignalA signal which is symmetrical about the vertical axis or time origin is known as even signal or even function. Therefore, the even signals are also called the symmetrical signals. Cosine wave is an example of even signal.Continuous-time Even SignalA continuous-time signal x(t) is called the even signal or ... Read More

Causal SignalA continuous time signal 𝑥(𝑡) is called causal signal if the signal 𝑥(𝑡) = 0 for 𝑡 < 0. Therefore, a causal signal does not exist for negative time. The unit step signal u(t) is an example of causal signal as shown in Figure-1.Similarly, a discrete time sequence x(n) ... Read More

Causal SystemA system whose output or response at any time instant (t) depends only on the present and past values of the input but not on the future values of the input is called the causal system. For a causal system, the output or response does not begin before the ... Read More

A sinusoidal function or sinusoidal signal is a function that describes a smooth periodic oscillation.Continuous-Time Sinusoidal SignalA sinusoidal signal which is defined for every instant of time is called continuous-time sinusoidal signal. The continuous time sinusoidal signal is given as follows −𝑥(𝑡) = 𝐴 sin(𝜔𝑡 + 𝜑) = 𝐴 sin(2𝜋𝑓𝑡 ... Read More

What is Time Shifting?Time shifting or Shifting of a signal in time means that the signal may be either delayed in the time axis or advanced in the time axis.Time Shifting of Continuous-Time SignalThe time shifting of a continuous time signal x(t) is represented as, 𝑦(𝑡) = 𝑥(𝑡 − 𝑡0)The ... Read More

What is Time Reversal of a Signal?The time reversal of a signal is folding of the signal about the time origin (or t = 0). The time reversal or folding of a signal is also called as the reflection of the signal about the time origin (or t = 0). ... Read More

Discrete Time SignalsThe signals which are defined only at discrete instants of time are known as discrete time signals. The discrete time signals are represented by x(n) where n is the independent variable in time domain.Representation of Discrete Time SignalsA discrete time signal may be represented by any one of ... Read More