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WorksheetsPrinciples Prelims-Midterm
Total questions: 60
Worksheet time: 30mins
It is the most used digital communication code.
Downlink
Morse Code
Continuous-Wave Code
American Standard Code for Information Interchange
It is used to produce smaller gains and attenuation by converting decibels.
Lambda
Logarithm
Input Power
Voltage Gain
He invented the telephone.
Heinrich Hertz
Samuel Morse
Tim Burners-Lee
Alexander Graham Bell
He is the pioneer of electromagnetics.
Heinrich Hertz
Samuel Morse
Tim Burners-Lee
Alexander Graham Bell
It is the loss fed by a circuit or component in a signal.
Gain
Signal
Digital
Attenuation
It defines all kinds of lights, even those human eyes cannot see.
Cycle
Spectra
Wavelength
Electromagnetic Spectrum
This carries the message on a fiber-optic cable or light pipe.
Receiver
Transmitter
Optical Media
Electrical Conductor
It is also referred to as radio telegraphy.
Downlink
Morse Code
Continuous-Wave Code
American Standard Code for Information Interchange
It is the amplification of a signal compared to its input signal.
Gain
Signal
Digital
Attenuation
This combines two or more electronic signals into one or two output signals.
Mixer
Amplifier
Oscillator
Tuned Circuit
These refer to electronic circuits that reduce the amplitude of a signal rather than increase it.
Gains
Stages
Analog
Decibels
It is the number of cycles of a repetitive wave that happen in a given period.
Hertz
Frequency
Wavelength
Power of 10
It is used to listen to underwater sounds with sensitive hydrophones.
Filter
Light Pipe
Free Space
Passive Sonar
It is a two-way communication wherein people can talk and listen simultaneously.
Simplex Communication
Duplex Communication
Full Duplex Communication
Half-Duplex Communication
It is used to express the hearing response of the human ear to sound levels.
Gain
Stage
Analog
Decibel
Which of the following statements best defines the function of a filter?
It produces a continuous waveform without input.
It produces a decreased version of the input signal.
It is capable of amplifying specific frequencies while attenuating others.
It combines an inductor and capacitor to make a circuit responsive to a frequency.
Which of the following transmissions DO NOT utilize half-duplex communications?
Fire Transmission
Military Transmission
Marine Radio Transmission
Customer Service Transmission
Which of the following statements is NOT TRUE about an analog signal?
It does not change continuously.
It can be found in video voltages.
It can be signals that vary based on sound or light variations.
It can be signals from physical characteristics detected by a sensor.
Which of the following frequencies is best used for two-way radios?
Very High Frequency
Ultra-High Frequency
Super High Frequency
Extremely High Frequency
Which of the following statements is NOT TRUE about the block diagram of communication systems?
It consists of five (5) blocks.
The last block is the receiver block.
The third block is the communication channel.
The blocks represent elements used in communication systems.
Which of the following best provides the gain to offset the attenuation?
The summation of all gains
The reciprocal of attenuation
The ratio of the output over the input
The summation of the overall attenuation
Which of the following DOES NOT best exemplify the use of a transmitter?
A microphone that converts the sound to an electronic audio signal.
A camera that converts light information in the scene to a video signal.
The use of oscillators to produce a repeated and alternating waveform without input.
The use of transducers to convert physical characteristics such as light intensity into electronic signals.
Which of the following frequency ranges falls within the voice frequency?
3–30 kHz
30–300 Hz
3–300 MHz
300–3000 Hz
Which of the following statements is NOT TRUE about attenuation?
It uses the same formula as gain.
It can be found in a circuit with a gain equal to 1.
It can be found in a circuit with a gain of less than 1.
It can be found in a circuit if the output signal is lower in amplitude than the input signal.
Which of the following statements best describes long signals used in Morse code?
They are represented as dots.
They are represented as dashes.
They are used to specifically represent letters.
They are used to specifically represent numbers.
Which of the following statements is NOT TRUE about a decibel?
It is expressed in dB.
It is one-tenth of a bel.
It is a unit of measurement.
It is the default unit for gain.
Which of the following statements is NOT TRUE about active sonar?
It is a type of transmitter.
It uses an echo-reflecting technique.
It determines the direction of underwater objects.
It determines how far away objects underwater are.
Which of the following statements best describes short signals used in Morse code?
They are represented as dots.
They are represented as dashes.
They are used to specifically represent letters.
They are used to specifically represent numbers.
Which of the following best simplifies a frequency of 32,500,000?
32.5 kHz
32.5 GHz
32.5 THz
32.5 MHz
Which of the following statements is NOT TRUE about duplex communication?
It can be a full or half-duplex.
It is a two-way communication.
It is utilized in telephone communications.
It happens when the uplink and downlink are separated.
It is the process of converting raw message data into digital signals over a modulator.
Modulation
Phase Modulation
Frequency Modulation
Amplitude Modulation
This modulation process puts the message in a carrier wave by changing the instantaneous frequency of the wave.
Modulation
Phase Modulation
Frequency Modulation
Amplitude Modulation
It is the imaginary line that connects the positive and negative peaks of the carrier waveform.
Linear
Envelope
Carrier Frequency
Steady Waveform
These are found in the frequency spectrum above and below the carrier frequency.
Envelopes
Sidebands
Frequencies
Carrier Signals
It is the amount of change in the carrier frequency caused by the modulating signal.
Phase Deviation
Phase-shift Keying
Frequency Deviation
Frequency-shift Keying
It is used to represent the frequency deviation in solving the modulation index of a frequency modulation signal.
fd
mf
df
fm
This modulation process is focused on changing the signal's amplitude.
Phase Modulation
Amplitude Modulation
Amplitude Modification
Frequency Modification
This is used to represent the modulating frequency in solving the modulation index of a frequency modulation signal.
fd
mf
df
fm
This is used to represent the modulation index in amplitude modulation.
m
mI
Mi
mod
It has a steady waveform in terms of amplitude and frequency.
Carrier Signal
Modulating Signal
Modulated Signal
Modulation Signal
It is the ratio of the amplitude of the modulating signal over the carrier signal.
Sideband
Phase Modulation
Modulation Index
Percentage of Modulation
This formula is used to solve the total bandwidth.
BW= (fUSB)(fLSB)
BW = fUSB + fLSB
BW = 3fm
BW = 2fm
It is another term used to refer to sidebands.
Side Signals
Carrier Waves
Side Frequencies
Frequency Signals
It is the mathematical process used in solving the FM signal equation.
Phase Deviation
Bessel Function
Modulation Index
Percentage of Modulation
It is a process wherein the phase modulation signal stretches at the positive peak of the modulating signal until the second zero deviation.
Lagging Phase Shift
Leading Phase Shift
Zero Deviation Shift
Phase Modulation Shift
Which of the following statements is TRUE about the amplitude of the modulating signal?
It must always be equal to the amplitude of the carrier.
It must always be less than the amplitude of the carrier.
It must always be more than the amplitude of the carrier.
It must always be twice as big as the amplitude of the carrier.
What is the modulating signal if the carrier voltage is 9 V and the modulation index is 0.3513?
0.0390 V
3.1617 V
8.6487 V
9.3513 V
What is the third lower sideband if the modulating frequency has 1 kHz and a carrier of 1 MHz?
0.97 MHz
1.003 MHz
997,000 Hz
1,003,000 Hz
What is the third upper sideband if the modulating frequency has 1 kHz and a carrier of 1 MHz?
0.97 MHz
1.003 MHz
997,000 Hz
1,003,000 Hz
In a frequency domain, what does the vertical axis represent?
Frequency
Waveform
Modulation Index
Magnitude of the Signal
Which of the following statements is NOT TRUE about the phase-shift keying process?
Shifting happens only if the signal is positive.
Signals do a phase shift when it hits binary 1 or 0.
Signals do a phase shift based on the given degree.
Shift happens whether the signal is positive or negative.
In frequency deviation, which of the following signs is used to indicate that the modulating signal changes the carrier above and below its center frequency?
+
±
==
< , >
Which of the following statements is NOT TRUE about amplitude modulation?
It allows the frequency to remain constant after modulation.
It allows a high-frequency signal to carry a low-frequency signal.
It uses the modulating signal to modify the amplitude of another signal.
It puts the message in a carrier wave by changing the instantaneous frequency of the wave.
Which of the following statements is NOT TRUE about the modulation process?
It optimizes data transmission.
It converts modulated signals into carrier signals.
It increases the strength of the signal to have maximum reach.
It improves signals often unsuitable for the transmission device.
Which of the following statements best describes frequency deviation?
It is expressed as the amount of frequency shift of the carrier above and below the center frequency.
It compresses signals based on the positive modulating signal.
It can be represented using binary signals.
It is unitless.
What is the modulation index if the carrier voltage is 9 V and the modulation signal is 3.7 V?
0.4111
41.11%
41.11 V
-0.4111 V
What is the maximum deviation if a signal has a 160 MHz carrier frequency and a maximum frequency of 30 kHz?
5.33 kHz
6.80 THz
160.03 MHz
159.97 MHz
Which of the following statements is NOT TRUE about a frequency-shift keying process?
The carrier frequency stretches if it is at binary 0.
The carrier frequency compresses if it is at binary 1.
The signals are represented based on Morse code values.
The amount of shift depends on the amplitude of the binary signal.
Which of the following is the preferred way to represent an AM signal in the frequency domain rather than the time domain?
If signals do not reach specific low values.
If signals do not reach specific peak values.
If signals of less than one (1) frequency create a waveform.
If signals of more than one (1) frequency create a waveform.
Which of the following can be considered a source of a carrier signal?
Mixer
Speaker
Antenna
Oscillator
