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SUBELEMENT G8 – SIGNALS AND EMISSIONS [3 Exam Questions – 3 Groups]

 

 

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G8A – Carriers and modulation: AM; FM; single sideband; modulation envelope; digital modulation; overmodulation

 

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G8A01

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

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G8A02

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

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G8A03

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

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G8A04

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

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G8A05

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

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G8A06

Which of the following is characteristic of QPSK31?

A. It is sideband sensitive

B. Its encoding provides error correction

C. Its bandwidth is approximately the same as BPSK31

D. All these choices are correct

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G8A07

Which of the following phone emissions uses the narrowest bandwidth?

A. Single sideband

B. Double sideband

C. Phase modulation

D. Frequency modulation

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G8A08

Which of the following is an effect of overmodulation?

A. Insufficient audio

B. Insufficient bandwidth

C. Frequency drift

D. Excessive bandwidth

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G8A09

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

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G8A10

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

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G8A11

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

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G8A12

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

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G8B – Frequency mixing; multiplication; bandwidths of various modes; deviation; duty cycle; intermodulation

 

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G8B01

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

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G8B02

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

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G8B03

What is another term for the mixing of two RF signals?

A. Heterodyning

B. Synthesizing

C. Cancellation

D. Phase inverting

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G8B04

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

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G8B05

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

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G8B06

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

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G8B07

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

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G8B08

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

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G8B09

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

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G8B10

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

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G8B11

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

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G8B12

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

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G8C – Digital emission modes

 

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G8C01

On what band do amateurs share channels with the unlicensed Wi-Fi service?

A. 432 MHz

B. 902 MHz

C. 2.4 GHz

D. 10.7 GHz

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G8C02

Which digital mode is used as a low-power beacon for assessing HF propagation?

A. WSPR

B. Olivia

C. PSK31

D. SSB-SC

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G8C03

What part of a packet radio frame contains the routing and handling information?

A. Directory

B. Preamble

C. Header

D. Footer

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G8C04

Which of the following describes Baudot code?

A. A 7-bit code with start, stop, and parity bits

B. A code using error detection and correction

C. A 5-bit code with additional start and stop bits

D. A code using SELCAL and LISTEN

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G8C05

In the PACTOR protocol, what is meant by a NAK response to a transmitted packet?

A. The receiver is requesting the packet be retransmitted

B. The receiver is reporting the packet was received without error

C. The receiver is busy decoding the packet

D. The entire file has been received correctly

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G8C06

What action results from a failure to exchange information due to excessive transmission attempts when using PACTOR or WINMOR?

A. The checksum overflows

B. The connection is dropped

C. Packets will be routed incorrectly

D. Encoding reverts to the default character set

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G8C07

How does the receiving station respond to an ARQ data mode packet containing errors?

A. It terminates the contact

B. It requests the packet be retransmitted

C. It sends the packet back to the transmitting station

D. It requests a change in transmitting protocol

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G8C08

Which of the following statements is true about PSK31?

A. Upper case letters are sent with more power

B. Upper case letters use longer Varicode bit sequences and thus slow down transmission

C. Error correction is used to ensure accurate message reception

D. Higher power is needed as compared to RTTY for similar error rates

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G8C09

What does the number 31 represent in “PSK31”?

A. The approximate transmitted symbol rate

B. The version of the PSK protocol

C. The year in which PSK31 was invented

D. The number of characters that can be represented by PSK31

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G8C10

How does forward error correction (FEC) allow the receiver to correct errors in received data packets?

A. By controlling transmitter output power for optimum signal strength

B. By using the Varicode character set

C. By transmitting redundant information with the data

D. By using a parity bit with each character

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G8C11

How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?

A. Dot and dash

B. On and off

C. High and low

D. Mark and space

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G8C12

Which type of code is used for sending characters in a PSK31 signal?

A. Varicode

B. Viterbi

C. Volumetric

D. Binary

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G8C13

What is indicated on a waterfall display by one or more vertical lines on either side of a digital signal?

A. Long path propagation

B. Backscatter propagation

C. Insufficient modulation

D. Overmodulation

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G8C14

Which of the following describes a waterfall display?

A. Frequency is horizontal, signal strength is vertical, time is intensity

B. Frequency is vertical, signal strength is intensity, time is horizontal

C. Frequency is horizontal, signal strength is intensity, time is vertical

D. Frequency is vertical, signal strength is horizontal, time is intensity

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