What is the main characteristic of a continuous-time signal?
A Discrete values
B Defined at specific times
C Defined at every instant
D Only periodic
Continuous-time signals are defined at every instant of time. This means that for every point in time, there exists a corresponding value of the signal. Examples include signals like voltage or current that vary continuously over time.
Which of the following is an example of a discrete-time signal?
A Sine wave
B Digital image
C Speech signal
D Temperature measurements
A discrete-time signal is one that is defined only at specific time intervals, unlike a continuous-time signal which is defined at every instant. A digital image consists of pixel values, which are sampled at discrete intervals.
What does the Fourier transform of a signal represent?
A Time-domain analysis
B System response
C Signal reconstruction
D Frequency-domain representation
The Fourier transform converts a time-domain signal into its frequency-domain representation. This transformation helps analyze the frequencies present in a signal and is essential for various applications like filtering and modulation.
What is the Laplace transform used for in system analysis?
A Frequency analysis
B Time-domain to frequency-domain transformation
C Solving differential equations
D Simplifying complex algebraic expressions
The Laplace transform is primarily used in system analysis to simplify the process of solving linear differential equations. It converts these equations from the time domain into the complex frequency domain, making it easier to analyze and solve.
Which of the following is a property of linear systems?
A Output depends on the current input only
B Output is proportional to the input
C Output depends on previous inputs only
D Output is not predictable
A linear system follows the principle of superposition, meaning that the output is directly proportional to the input. If the input is scaled, the output will scale by the same factor, demonstrating linearity.
What does the Nyquist rate relate to in signal processing?
A Sampling rate
B Bandwidth
C Signal reconstruction
D Signal modulation
The Nyquist rate is the minimum sampling rate required to avoid aliasing when converting a continuous-time signal into a discrete-time signal. It must be at least twice the maximum frequency present in the signal.
What does the impulse response of a system describe?
A The system’s output for a constant input
B The system’s input-output relationship
C The system’s response to a unit impulse input
D The system’s frequency response
The impulse response of a system is the output of the system when the input is a unit impulse. It characterizes how the system reacts to a sudden, brief input and is fundamental in analyzing linear time-invariant systems.
Which of the following is a causal system?
A The output depends on current inputs only
B The output depends on past inputs
C The output depends on future inputs
D The output depends only on past and present inputs
A causal system is one in which the output at any time depends only on the current and past inputs, never future inputs. This property ensures that the system is physically realizable and can be implemented in real-time.
What does the Z-transform mainly deal with?
A Time-domain analysis of discrete signals
B Discrete-time signal processing
C Frequency-domain analysis of continuous signals
D Time-domain analysis of continuous signals
The Z-transform is primarily used for analyzing and processing discrete-time signals. It transforms discrete signals from the time domain into a complex frequency domain, which is useful for solving difference equations and analyzing system behavior.
What is bandwidth in the context of signal processing?
A The highest frequency of the signal
B The signal’s amplitude range
C The range of frequencies that a signal occupies
D The lowest frequency of the signal
Bandwidth refers to the range of frequencies that a signal occupies. It determines how much frequency space the signal takes up in the frequency domain and is critical for applications such as communication and signal processing.
What is the primary purpose of signal modulation?
A To convert the signal to a higher frequency for transmission
B To change the frequency of the signal
C To remove noise from the signal
D To amplify the signal
Signal modulation involves varying the signal’s frequency, amplitude, or phase to encode information for transmission over a carrier wave. This allows the signal to travel long distances and avoids interference with other signals.
What does time invariance in a system imply?
A The system’s response changes with time
B The system only works at specific times
C The system is not predictable
D The system’s behavior is consistent over time
A time-invariant system is one where the system’s properties do not change over time. The output response to a given input will always be the same, regardless of when the input is applied, making the system predictable.
What is noise in the context of signal processing?
A Signal distortion due to system overload
B A high-frequency component of the signal
C Unwanted random fluctuations in a signal
D A low-frequency component of the signal
Noise refers to any unwanted random fluctuations or disturbances that interfere with the desired signal. It can degrade the quality of the signal and is often mitigated through noise reduction techniques in signal processing.
Which of the following is true about analog signals?
A They are quantized and discrete
B They exist in digital form
C They are sampled for processing
D They are continuous in both time and amplitude
Analog signals are continuous in both time and amplitude. This means they can take on any value within a given range and are typically represented as smooth waveforms, unlike digital signals that are discrete in nature.
What is the main goal of the sampling theorem?
A To ensure no loss of information during sampling
B To reduce signal bandwidth
C To convert analog signals into digital form
D To eliminate noise from signals
The sampling theorem states that an analog signal can be completely represented in digital form if it is sampled at a rate greater than twice the highest frequency of the signal. This prevents information loss and aliasing during the sampling process.