What is the main characteristic of a continuous-time signal?
A Discrete
B Sampled
C Analog
D Constant
Continuous-time signals are represented by analog values and are defined at every instant of time, unlike discrete signals which are defined only at specific intervals. These signals can take any value within a range.
What does a system’s frequency response describe?
A Time-domain analysis
B Behavior for periodic inputs
C Signal bandwidth
D Output for constant input
The frequency response of a system describes how the system behaves when subjected to periodic inputs. It shows how different frequencies are attenuated or amplified by the system, helping in the design of filters and systems.
What is the primary objective of sampling in signal processing?
A Encode information
B Filter frequencies
C Convert analog to digital
D Amplify signal
Sampling is the process of converting a continuous-time analog signal into a discrete-time signal by taking periodic samples. This enables the signal to be processed using digital techniques, such as in digital signal processing.
What is the purpose of the Laplace transform in system analysis?
A Simplify time-domain analysis
B Analyze system response
C Convert signals to frequency domain
D Solve algebraic equations
The Laplace transform is used to convert time-domain signals into the s-domain, simplifying the analysis of linear systems, particularly for solving differential equations. It helps in analyzing system stability and behavior.
What does the time-domain representation of a signal show?
A Frequency content
B Noise levels
C Amplitude variations over time
D Phase shifts
The time-domain representation of a signal shows how the signal’s amplitude changes over time. It provides a direct view of the signal’s behavior at each instant, which is essential for signal processing and analysis.
What type of signal is described by a finite number of values over time?
A Continuous
B Periodic
C Discrete
D Sinusoidal
A discrete-time signal consists of a finite set of values defined at specific time intervals. These signals are typically generated by sampling continuous-time signals and are used in digital systems for further processing.
Which of the following best defines a linear system?
A Output depends on current and future inputs
B Output is a weighted sum of inputs
C Output depends on current input
D Output depends on random factors
A linear system obeys the principle of superposition, meaning that its output is a weighted sum of its inputs. This property simplifies analysis and allows for the design of predictable and stable systems.
In the frequency domain, what does a low-pass filter do?
A Amplifies high frequencies
B Passes high frequencies
C Attenuates high frequencies
D Passes low frequencies
A low-pass filter allows low-frequency signals to pass through while attenuating higher frequencies. It is commonly used to remove high-frequency noise from signals, leaving only the desired lower-frequency components.
What is the primary function of a modulator in signal processing?
A Increase amplitude
B Remove noise
C Change frequency
D Convert digital to analog
A modulator changes the frequency of a signal to encode information for transmission. This process allows signals to be transmitted over longer distances by shifting them to a higher frequency band suitable for the communication medium.
Which of the following is a property of causal systems?
A Output is random
B Output depends only on present and past inputs
C Output depends on future and past inputs
D Output depends on future inputs
A causal system’s output at any given time depends only on the current and past inputs, never on future inputs. This makes causal systems physically realizable and suitable for real-time processing.
What does the convolution operation describe in a system?
A System stability
B Interaction between two signals
C Signal amplification
D Signal noise reduction
Convolution describes how two signals interact to produce a system’s output. It is an essential operation for analyzing linear time-invariant systems, as it combines the input signal with the system’s impulse response to generate the output.
What does the term “bandwidth” refer to in signal processing?
A Range of frequencies
B Time duration
C Signal strength
D Signal speed
Bandwidth refers to the range of frequencies occupied by a signal. It defines how much frequency spectrum a signal uses, influencing how much data can be transmitted and the quality of communication.
In the context of digital signals, what does quantization refer to?
A Sampling signal values
B Filtering noise
C Converting continuous values to discrete levels
D Amplifying signal strength
Quantization is the process of converting the continuous amplitude values of an analog signal into discrete values. This process is essential in digital signal processing, where the signal must be represented with a finite set of possible levels.
What is the primary role of a demodulator in communication systems?
A Increase signal strength
B Convert digital to analog
C Change frequency
D Extract information from modulated signals
A demodulator is responsible for extracting the original information from a modulated signal. It performs the inverse operation of modulation, recovering the encoded data from the signal for further processing or interpretation.
What does a system’s impulse response help determine?
A System output to any input
B Frequency response
C Stability
D Bandwidth
The impulse response of a system helps determine its output for any arbitrary input through convolution. It characterizes the system’s behavior and is fundamental for understanding how the system processes signals over time.