What does signal modulation achieve in communication systems?
A Signal reconstruction
B Signal compression
C Noise removal
D Frequency conversion
Modulation changes the frequency, amplitude, or phase of a carrier signal to encode information. This allows signals to be transmitted over long distances without interference and is essential in communication systems like radio and TV broadcasting.
What is the primary goal of systems classification in signal processing?
A Signal amplification
B Signal encoding
C System analysis
D Filter design
Systems classification helps in analyzing and categorizing systems based on their characteristics, such as linearity, time invariance, and causality. It is crucial for selecting appropriate techniques for analyzing and designing systems.
Which of the following is a characteristic of linear systems?
A Output is directly proportional to input
B Output depends on future inputs
C Output is random
D Output depends on past inputs
A linear system follows the principle of superposition, where the output is directly proportional to the input. This makes such systems predictable and easier to analyze mathematically, which is vital in many signal processing applications.
What type of modulation varies the amplitude of a carrier signal?
A FM
B AM
C PSK
D PM
Amplitude Modulation (AM) varies the amplitude of the carrier signal in accordance with the message signal. It is widely used in radio broadcasting and other communication systems for transmitting information over long distances.
What does a band pass filter allow in signal processing?
A Low frequencies
B All frequencies
C High frequencies
D Specific range of frequencies
A band pass filter passes signals within a specific frequency range while attenuating signals outside that range. It is widely used in communication systems to isolate certain frequencies and remove unwanted noise or interference.
What is the effect of signal modulation on a carrier wave?
A Changes the phase
B Increases frequency
C Increases amplitude
D None of the above
Modulation changes the carrier wave’s frequency, amplitude, or phase to encode the signal’s information. This makes the signal suitable for transmission over communication channels, where it can travel long distances without significant loss.
Which of the following is true for a time invariant system?
A Output shifts with delayed input
B Output changes with time
C Output depends on time
D Output is not predictable
A time invariant system’s response to an input is always the same regardless of when the input is applied. If the input is delayed, the output will also be delayed by the same amount, demonstrating time invariance.
What is the primary purpose of Phase Modulation (PM)?
A Increase bandwidth
B Change phase
C Reduce signal power
D Change frequency
Phase Modulation (PM) encodes the information by varying the phase of the carrier signal. It is a type of modulation used in various communication systems, including digital communication, to improve signal robustness and reduce interference.
Which of the following is a property of a memoryless system?
A Output depends on past inputs
B Output depends on current input
C Output depends on both past and future inputs
D Output depends on future inputs
A memoryless system produces an output based solely on the current input, with no reliance on past or future inputs. This makes such systems simpler and more straightforward to analyze and implement in signal processing tasks.
What does a high pass filter do?
A Blocks all frequencies
B Attenuates all frequencies
C Passes high frequencies
D Passes low frequencies
A high pass filter allows signals with frequencies above a certain cutoff frequency to pass while attenuating lower frequencies. This is useful for removing low frequency noise and preserving high frequency components in a signal.
What is the purpose of a low pass filter in signal processing?
A Amplify low frequency signals
B Isolate low frequency components
C Remove high frequency noise
D All of the above
A low pass filter passes low frequency signals while attenuating high frequency components. It is used to remove high frequency noise, smooth out signals, and isolate the desired low frequency components in applications like audio and sensor data processing.
Which modulation technique is most commonly used in FM radio broadcasting?
A FM
B PSK
C AM
D PM
Frequency Modulation (FM) is widely used in radio broadcasting due to its resilience to noise and its ability to provide higher sound quality. In FM, the frequency of the carrier signal is varied in proportion to the input signal.
What does the process of demodulation do?
A Amplifies the signal
B Decodes the transmitted information
C Filters signal noise
D Converts signal from analog to digital
Demodulation is the process of extracting the original information from a modulated signal. It reverses the modulation process, allowing the receiver to decode the transmitted data and retrieve the message or information encoded in the signal.
What is the primary function of a band stop filter?
A Allow high frequencies
B Allow all frequencies
C Reject frequencies within a specific range
D Pass only low frequencies
A band stop filter attenuates frequencies within a specific range while allowing frequencies outside of this range to pass. It is useful for eliminating unwanted frequency bands, such as interference from power lines in communication systems.
What type of system’s output depends only on past and current inputs?
A Linear
B Causal
C Time varying
D Non causal
A causal system produces an output based on the current and past inputs but never future inputs. This makes causal systems practical for real time applications, where future inputs are not available during processing.