Deck 3: Angle Modulation

Question 1

Almost all FM transmissions provide an artificial boost to the electrical amplitude of the higher frequencies. What is this process called?
A.Deemphasis
B.Capture effect
C.Noise suppression
D.Preemphasis

Answer 1

Preemphasis

Question 2

Which of the following would be an example a "wideband" FM application?
A.Two-way radio
B.Oscillator
C.Radio transmitter
D.Broadcasting

Answer 2

Broadcasting

Question 3

What factor determines the amount of carrier frequency deviation?
A.Intelligence frequency
B.Changing frequency
C.Frequency components
D.Intelligence amplitude

Answer 3

Intelligence amplitude

Question 4

Modulation function of a direct-FM transmitter is contained within the ____________.
A.microphone
B.oscillator
C.sideband
D.signal

Question 5

Determining the ____________ is the first step in determining the occupied bandwidth of the modulated carrier.
A.frequency-modulated signal
B.cyclical amplitude variations
C.modulation index
D.side-frequency amplitudes

Question 6

Why is the capacitor microphone FM generation system seldom used in practical radio-frequency transmission applications?
A.It is inherently unstable.
B.It causes the carrier to shift.
C.It depends on the amplitude and frequency of the modulating signal.
D.It is dependent on system design.

Question 7

What type of tables show the number of significant side frequencies and the relative amplitudes in each set of side frequencies as well as in the carrier?
A.FM spectrum
B.Bessel
C.Carson
D.Zero-carrier

Question 8

The frequency of the modulating signal does not affect deviation in _________.
A.AM
B.FM
C.PM
D.MHz

Question 9

______________ occurs when the modulating signal causes the instantaneous carrier phase,rather than its frequency,to shift from its reference value.
A.Angular velocity
B.Phase shifts
C.Phase modulation
D.Rest frequency

Question 10

What causes the FM receiver to lock on the stronger signal by suppressing the weaker but can fluctuate back and forth when the two are nearly equal?
A.Preemphasis
B.Deemphasis
C.Amplification
D.Capture effect

Question 11

The amount by which the oscillator frequency increases and decreases from is called_________.
A.amplitude modulation
B.frequency modulation
C.frequency deviation
D.rest frequency

Question 12

What is the most important advantage of FM over AM?
A.FM is completely insensitive to noise.
B.FM has superior noise characteristics.
C.PM signal can be made to look like FM.
D.Phase modulation (PM) can be used to create FM indirectly.

Question 13

Which of the following describes the maximum deviation permitted by law or regulation?
A.FM percentage of modulation
B.Deviation ratio (DR)
C.Phase modulation
D.Angular velocity

Question 14

Why would a lightning strike be a concern for AM radios?
A.Frequency and phase modulation are interrelated.
B.Bandwidth is twice the highest intelligence frequency.
C.AM receiver susceptible to external electrical noise.
D.Modulation increases the total transmitted power.

Question 15

_____________and phase modulation are interrelated.
A.Frequency
B.Bandwidth
C.Voltage
D.Intelligence

Question 16

What mathematical tool is used to solve for the frequency components of the frequency-modulated signal?
A.Bessel function
B.Modulation index
C.Deviation ratio
D.Percentage of modulation

Question 17

_____________ are defined as those requiring more bandwidth than would be occupied by AM transmissions with the same maximum intelligence frequency.
A.AM broadcast transmissions
B.Specialized mobile radios (SMRs)
C.Narrowband FM transmissions
D.Wideband FM transmissions

Question 18

___________ is used to predict the bandwidth necessary for an FM signal.
A.Carson's rule
B.Ohm's law
C.Spectrum analysis
D.Bessel functions

Question 19

Which of the following is a drawback to direct FM systems?
A.Preserving both the amplitude and frequency characteristics of the intelligence.
B.Maintaining the frequency stability of the transmitter.
C.Narrowband FM systems occupy less bandwidth.
D.Modulation index for FM systems is stable.

Question 20

All communications systems are constrained by_____________.
A.bandwidth availability
B.reference frequency
C.sound waves
D.absence of modulation

Question 21

___________ always appear in pairs,one above and one below the carrier.
A.Side frequencies
B.Occupied bandwidths
C.Waveforms
D.Carrier nulls

Question 22

What does the AM modulation index measure?
A.Modulation depth
B.Intelligence frequencies
C.Amplitude variations
D.Normalized voltages

Question 23

Which of the following is used primarily for two-way voice communication rather than entertainment?
A.Wideband FM
B.Guard bands
C.Narrowband FM (NBFM) systems
D.Specialized mobile radios (SMRs)

Question 24

Which of the following is (are)always equal to twice the highest frequency of the modulating signal,regardless of its amplitude?
A.FM bandwidth
B.Frequency deviation
C.AM bandwidth
D.Frequency domains

Question 25

Determining __________ rests on determining where the power resides in the modulated signal.
A.angular velocity
B.intelligence
C.bandwidth
D.intelligence frequency