In signals and systems, the concepts of causal and non-causal systems describe how the output of a system depends on the input signal with respect to time. Causal System A causal system is a system in which the output at any time depends only on the present input and past inputs, but not on future …
The impulse response is one of the most important concepts in signals and systems. It represents the output of a system when the input is a unit impulse signal. The impulse response completely characterizes a Linear Time-Invariant (LTI) system, meaning that once the impulse response is known, the output of the system for any input …
The group delay of a filter is an important concept in digital signal processing (DSP) that describes how different frequency components of a signal are delayed while passing through a system. It is particularly important when analyzing recursive filters, also known as Infinite Impulse Response (IIR) filters. Group delay helps determine how a filter affects …
A non-recursive filter is a type of digital filter in which the current output depends only on the present and past input values, and not on previous output values. These filters do not use feedback, and therefore their structure contains only feedforward paths. Non-recursive filters are commonly known as Finite Impulse Response (FIR) filters and …
A diode is a fundamental two-terminal semiconductor device that allows electric current to flow primarily in one direction while blocking current in the opposite direction. Because of this property, it is widely used in rectification, switching, signal detection, and voltage regulation circuits. Structure of a Diode A diode is formed by joining P-type semiconductor and …
The Nyquist Sampling Theorem is a fundamental principle in signal processing and communication systems. It states the minimum sampling rate required to convert a continuous-time signal into a discrete-time signal without losing information. Statement of Nyquist Sampling Theorem The Nyquist sampling theorem states: “A band-limited signal can be perfectly reconstructed from its samples if the …
Ideal sampling is the theoretical process of converting a continuous-time signal into a discrete-time signal by multiplying the signal with a train of impulse functions. In this method, the signal is sampled at exact instants of time, producing impulses whose amplitudes are equal to the instantaneous value of the signal. Ideal sampling is mainly …
Natural sampling is a sampling technique used in communication systems where the continuous-time signal is multiplied by a periodic train of rectangular pulses. In this method, the top of each sampling pulse follows the shape of the input signal rather than remaining constant. Natural sampling is an intermediate method between ideal sampling and flat-top sampling …
Flat-top sampling is a practical sampling technique used in analog-to-digital conversion (ADC) and pulse amplitude modulation (PAM) systems. Unlike ideal sampling, where samples are represented by impulses, flat-top sampling holds the sampled value constant for a short duration, producing pulses with flat tops. This method is widely used in real electronic systems because it is …
A Linear Time-Invariant (LTI) system is a fundamental concept in signal processing, control systems, and communication engineering. Such systems are characterized by two important properties: linearity and time invariance. Because of these properties, LTI systems are mathematically convenient and widely used for analyzing signals and systems. Linearity Property A system is said to be linear …