The system response refers to the output produced by a system when a certain input is applied. It is essential for understanding how the system processes signals and for evaluating system performance in various conditions.
What does the impulse response of a system represent?
A Output for any input
B Input to the system
C System’s stability
D System’s output for a unit impulse
The impulse response of a system is its output when a unit impulse (Dirac delta function) is applied as the input. It fully characterizes the system’s behavior and is used to predict output for any arbitrary input using convolution.
What is a key characteristic of a linear system?
A Output is the weighted sum of inputs
B Output depends on past and future inputs
C Output is random
D Output depends only on current input
A linear system follows the principle of superposition, meaning that its output for multiple inputs is the weighted sum of the outputs for each input individually. This property makes linear systems easier to analyze and predict.
What does a system’s time invariance property imply?
A System’s output depends on input delay
B Output changes with time of day
C Output shifts with delayed input
D System’s behavior changes over time
A time invariant system produces the same output for a given input, regardless of when the input is applied. If the input is delayed, the output will also be delayed by the same amount, preserving system behavior over time.
Which of the following describes a causal system?
A Output depends on future inputs
B Output depends on current and past inputs
C Output depends on past inputs only
D Output depends on random factors
A causal system’s output at any given time depends only on the present and past inputs. This makes it physically realizable and ensures that it can be implemented in real time systems without future input knowledge.
What does a stable system produce for a bounded input?
A Infinite output
B Noise
C Unpredictable output
D Bounded output
A stable system ensures that for any bounded input, the output will also be bounded. This property is crucial for ensuring that the system does not produce erratic or unmanageable outputs, making it reliable for practical use.
What is the bandwidth of a signal?
A The range of frequencies it occupies
B The number of samples required
C The maximum amplitude of the signal
D The time duration of the signal
Bandwidth refers to the range of frequencies that a signal occupies in the frequency spectrum. It is an important factor in communication systems because it determines how much data can be transmitted within a given time period.
What is the Nyquist rate in sampling?
A Sampling rate is fixed
B Sampling rate equals the bandwidth
C Sampling rate is twice the signal’s highest frequency
D Sampling rate is equal to the signal’s frequency
The Nyquist rate specifies the minimum sampling rate required to prevent aliasing. It is at least twice the maximum frequency component of the signal, ensuring that no information is lost during the conversion from continuous to discrete form.
What does signal modulation primarily involve?
A Reducing signal bandwidth
B Encoding information onto a carrier signal
C Attenuating noise
D Increasing signal strength
Signal modulation involves varying the properties of a carrier wave (such as its amplitude, frequency, or phase) to encode information for transmission. This allows signals to travel over long distances without interference and efficiently carry data.
What is the primary purpose of a demodulator in a communication system?
A Extract the original information
B Remove noise
C Amplify the signal
D Modulate the signal
A demodulator extracts the original information from a modulated carrier signal. It performs the inverse operation of modulation, allowing the receiver to decode the transmitted data and retrieve the message or information encoded in the signal.
What happens when a signal is sampled at a rate lower than the Nyquist rate?
A Signal is amplified
B Aliasing occurs
C Signal is correctly reconstructed
D Signal is distorted
When a signal is sampled at a rate lower than the Nyquist rate, aliasing occurs. This results in high frequency components being misrepresented as lower frequencies, leading to distortion and errors in signal reconstruction.
What does the Fourier transform convert in signal processing?
A Digital signal to time domain
B Time domain signal to frequency domain
C Analog signal to digital
D Frequency domain signal to time domain
The Fourier transform is used to convert a time domain signal into its frequency domain representation. This transformation allows for analysis of the signal’s frequency components, making it easier to filter, modulate, or reconstruct signals.
What is the purpose of filter design in signal processing?
A Convert signals from analog to digital
B Amplify all frequencies
C Isolate desired frequencies
D Remove all signals
Filter design aims to isolate specific frequencies while attenuating others. Filters are used in a variety of applications, including noise reduction, signal reconstruction, and communication, to ensure that only the desired frequency components are passed.
What does noise in a signal primarily affect?
A Signal clarity
B Signal modulation
C Frequency components
D Signal power
Noise introduces unwanted random fluctuations into a signal, which distorts the original message. It reduces the clarity of the signal, making it harder to detect or process, and requiring noise reduction techniques to improve the signal quality.
What does signal reconstruction involve?
A Increasing signal strength
B Removing noise
C Changing signal amplitude
D Converting digital signals to analog
Signal reconstruction refers to converting a digital signal back into its original continuous time (analog) form. This is typically achieved through interpolation techniques that restore the continuous nature of the signal from its discrete samples.