G8 – SIGNALS AND EMISSIONS [3 Exam Questions – 3 Groups] Flashcards
How is an FSK signal generated?
A. By keying an FM transmitter with a sub-audible tone
B. By changing an oscillator’s frequency directly with a digital control signal
C. By using a transceiver’s computer data interface protocol to change frequencies
D. By reconfiguring the CW keying input to act as a tone generator
G8A01 (B)
B. By changing an oscillator’s frequency directly with a digital control signal
What is the name of the process that changes the phase angle of an RF signal to convey information?
A. Phase convolution
B. Phase modulation
C. Phase transformation
D. Phase inversion
G8A02 (B)
B. Phase modulation
What is the name of the process that changes the instantaneous frequency of an RF wave to convey information?
A. Frequency convolution
B. Frequency transformation
C. Frequency conversion
D. Frequency modulation
G8A03 (D)
D. Frequency modulation
What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?
A. Multiplex modulation
B. Phase modulation
C. Amplitude modulation
D. Pulse modulation
G8A04 (B)
B. Phase modulation
What type of modulation varies the instantaneous power level of the RF signal?
A. Frequency shift keying
B. Phase modulation
C. Frequency modulation
D. Amplitude modulation
G8A05 (D)
D. Amplitude modulation
Which of the following is characteristic of QPSK31?
A. It is sideband sensitive
B. It has forward error correction
C. The bandwidth is slightly higher than BPSK31
D. All these choices are correct
G8A06 (C)
C. The bandwidth is slightly higher than BPSK31
Which of the following phone emissions uses the narrowest bandwidth?
A. Single sideband
B. Double sideband
C. Phase modulation
D. Frequency modulation
G8A07 (A)
A. Single sideband
Which of the following is an effect of overmodulation?
A. Insufficient audio
B. Insufficient bandwidth
C. Frequency drift
D. Excessive bandwidth
G8A08 (D)
D. Excessive bandwidth
What type of modulation is used by the FT8 digital mode?
A. 8-tone frequency shift keying
B. Vestigial sideband
C. Amplitude compressed AM
D. Direct sequence spread spectrum
G8A09 (A)
A. 8-tone frequency shift keying
What is meant by the term “flat-topping,” when referring to a single sideband phone transmission?
A. Signal distortion caused by insufficient collector current
B. The transmitter’s automatic level control (ALC) is properly adjusted
C. Signal distortion caused by excessive drive
D. The transmitter’s carrier is properly suppressed
G8A10 (C)
C. Signal distortion caused by excessive drive
What is the modulation envelope of an AM signal?
A. The waveform created by connecting the peak values of the modulated signal
B. The carrier frequency that contains the signal
C. Spurious signals that envelop nearby frequencies
D. The bandwidth of the modulated signal
G8A11 (A)
A. The waveform created by connecting the peak values of the modulated signal
Which of the following narrow-band digital modes can receive signals with very low signal-to-noise ratios?
A. MSK144
B. FT8
C. AMTOR
D. MFSK32
G8A12 (B)
B. FT8
Which mixer input is varied or tuned to convert signals of different frequencies to an intermediate frequency (IF)?
A. Image frequency
B. Local oscillator
C. RF input
D. Beat frequency oscillator
G8B01 (B)
B. Local oscillator
If a receiver mixes a 13.800 MHz VFO with a 14.255 MHz received signal to produce a 455 kHz intermediate frequency (IF) signal, what type of interference will a 13.345 MHz signal produce in the receiver?
A. Quadrature noise
B. Image response
C. Mixer interference
D. Intermediate interference
G8B02 (B)
B. Image response
What is another term for the mixing of two RF signals?
A. Heterodyning
B. Synthesizing
C. Cancellation
D. Phase inverting
G8B03 (A)
A. Heterodyning
What is the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency?
A. Mixer
B. Reactance modulator
C. Pre-emphasis network
D. Multiplier
G8B04 (D)
D. Multiplier
What is the approximate bandwidth of a PACTOR-III signal at maximum data rate?
A. 31.5 Hz
B. 500 Hz
C. 1800 Hz
D. 2300 Hz
G8B05 (D)
D. 2300 Hz
What is the total bandwidth of an FM phone transmission having 5 kHz deviation and 3 kHz modulating frequency?
A. 3 kHz
B. 5 kHz
C. 8 kHz
D. 16 kHz
G8B06 (D)
D. 16 kHz
What is the frequency deviation for a 12.21 MHz reactance modulated oscillator in a 5 kHz deviation, 146.52 MHz FM phone transmitter?
A. 101.75 Hz
B. 416.7 Hz
C. 5 kHz
D. 60 kHz
G8B07 (B)
B. 416.7 Hz
Why is it important to know the duty cycle of the mode you are using when transmitting?
A. To aid in tuning your transmitter
B. Some modes have high duty cycles that could exceed the transmitter’s average power rating
C. To allow time for the other station to break in during a transmission
D. The attenuator will have to be adjusted accordingly
G8B08 (B)
B. Some modes have high duty cycles that could exceed the transmitter’s average power rating
Why is it good to match receiver bandwidth to the bandwidth of the operating mode?
A. It is required by FCC rules
B. It minimizes power consumption in the receiver
C. It improves impedance matching of the antenna
D. It results in the best signal-to-noise ratio
G8B09 (D)
D. It results in the best signal-to-noise ratio
What is the relationship between transmitted symbol rate and bandwidth?
A. Symbol rate and bandwidth are not related
B. Higher symbol rates require wider bandwidth
C. Lower symbol rates require wider bandwidth
D. Bandwidth is always half the symbol rate
G8B10 (B)
B. Higher symbol rates require wider bandwidth
What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output?
A. The ratio
B. The average
C. The sum and difference
D. The arithmetic product
G8B11 (C)
C. The sum and difference
What process combines two signals in a non-linear circuit or connection to produce unwanted spurious outputs?
A. Intermodulation
B. Heterodyning
C. Detection
D. Rolloff
G8B12 (A)
A. Intermodulation