General Class License Exam Questions

Subelement G8

Signals and Emissions

Groups

G8A - Carriers and modulation; AM; FM; single sideband; modulation envelope; digital modulation; over modulation
G8B - Frequency mixing; multiplication; bandwidths of various modes; deviation
G8C - Digital emission modes

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Group G8A Carriers and modulation; AM; FM; single sideband; modulation envelope; digital modulation; over modulation

G8A01 How is an FSK signal generated?

By keying an FM transmitter with a sub-audible tone
By changing an oscillator's frequency directly with a digital control signal
By using a transceiver's computer data interface protocol to change frequencies
By reconfiguring the CW keying input to act as a tone generator

G8A02 What is the name of the process that changes the phase angle of an RF wave to convey information?

Phase convolution
Phase modulation
Angle convolution
Radian inversion

G8A03 What is the name of the process that changes the instantaneous frequency of an RF wave to convey information?

Frequency convolution
Frequency transformation
Frequency conversion
Frequency modulation

G8A04 What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?

Multiplex modulation
Phase modulation
Amplitude modulation
Pulse modulation

G8A05 What type of modulation varies the instantaneous power level of the RF signal?

Frequency shift keying
Phase modulation
Frequency modulation
Amplitude modulation

G8A06 What is one advantage of carrier suppression in a single sideband phone transmission versus full carrier amplitude modulation?

Audio fidelity is improved
Greater modulation percentage is obtainable with lower distortion
Available transmitter power can be used more effectively
Simpler receiving equipment can be used

G8A07 Which of the following phone emissions uses the narrowest bandwidth?

Single sideband
Double sideband
Phase modulation
Frequency modulation

G8A08 Which of the following is an effect of overmodulation?

Insufficient audio
Insufficient bandwidth
Frequency drift
Excessive bandwidth

G8A09 What control is typically adjusted for proper ALC setting on an amateur single sideband transceiver?

The RF clipping level
Transmit audio or microphone gain
Antenna inductance or capacitance
Attenuator level

G8A10 What is meant by the term flat-topping when referring to a single sideband phone transmission?

Signal distortion caused by insufficient collector current
The transmitter's automatic level control (ALC) is properly adjusted
Signal distortion caused by excessive drive
The transmitter's carrier is properly suppressed

G8A11 What is the modulation envelope of an AM signal?

The waveform created by connecting the peak values of the modulated signal
The carrier frequency that contains the signal
Spurious signals that envelop nearby frequencies
The bandwidth of the modulated signal

Group G8B Frequency mixing; multiplication; bandwidths of various modes; deviation

G8B01 What receiver stage combines a 14.250 MHz input signal with a 13.795 MHz oscillator signal to produce a 455 kHz intermediate frequency (IF) signal?

Mixer
BFO
VFO
Discriminator

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?

Quadrature noise
Image response
Mixer interference
Intermediate interference

G8B03 What is another term for the mixing of two RF signals?

Heterodyning
Synthesizing
Cancellation
Phase inverting

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?

Mixer
Reactance modulator
Pre-emphasis network
Multiplier

G8B05 What is the approximate bandwidth of a PACTOR3 signal at maximum data rate?

31.5 Hz
500 Hz
1800 Hz
2300 Hz

G8B06 What is the total bandwidth of an FM phone transmission having 5 kHz deviation and 3 kHz modulating frequency?

3 kHz
5 kHz
8 kHz
16 kHz

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?

101.75 Hz
416.7 Hz
5 kHz
60 kHz

G8B08 Why is it important to know the duty cycle of the mode you are using when transmitting?

To aid in tuning your transmitter
Some modes have high duty cycles which could exceed the transmitter's average power rating
To allow time for the other station to break in during a transmission
All of these choices are correct

G8B09 Why is it good to match receiver bandwidth to the bandwidth of the operating mode?

It is required by FCC rules
It minimizes power consumption in the receiver
It improves impedance matching of the antenna
It results in the best signal to noise ratio

G8B10 What is the relationship between transmitted symbol rate and bandwidth?

Symbol rate and bandwidth are not related
Higher symbol rates require wider bandwidth
Lower symbol rates require wider bandwidth
Bandwidth is always half the symbol rate

Group G8C Digital emission modes

G8C01 Which of the following digital modes is designed to operate at extremely low signal strength on the HF bands?

FSK441 and Hellschreiber
JT9 and JT65
Clover
RTTY

G8C02 How many data bits are sent in a single PSK31 character?

The number varies
5
7
8

G8C03 What part of a data packet contains the routing and handling information?

Directory
Preamble
Header
Footer

G8C04 Which of the following describes Baudot code?

A 7-bit code with start, stop and parity bits
A code using error detection and correction
A 5-bit code with additional start and stop bits
A code using SELCAL and LISTEN

G8C05 In the PACTOR protocol, what is meant by an NAK response to a transmitted packet?

The receiver is requesting the packet be retransmitted
The receiver is reporting the packet was received without error
The receiver is busy decoding the packet
The entire file has been received correctly

G8C06 What action results from a failure to exchange information due to excessive transmission attempts when using PACTOR or WINMOR?

The checksum overflows
The connection is dropped
Packets will be routed incorrectly
Encoding reverts to the default character set

G8C07 How does the receiving station respond to an ARQ data mode packet containing errors?

It terminates the contact
It requests the packet be retransmitted
It sends the packet back to the transmitting station
It requests a change in transmitting protocol

G8C08 Which of the following statements is true about PSK31?

Upper case letters make the signal stronger
Upper case letters use longer Varicode signals and thus slow down transmission
Varicode Error Correction is used to ensure accurate message reception
Higher power is needed as compared to RTTY for similar error rates

G8C09 What does the number 31 represent in "PSK31"?

The approximate transmitted symbol rate
The version of the PSK protocol
The year in which PSK31 was invented
The number of characters that can be represented by PSK31

G8C10 How does forward error correction (FEC) allow the receiver to correct errors in received data packets?

By controlling transmitter output power for optimum signal strength
By using the varicode character set
By transmitting redundant information with the data
By using a parity bit with each character

G8C11 How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?

Dot and Dash
On and Off
High and Low
Mark and Space

G8C12 Which type of code is used for sending characters in a PSK31 signal?

Varicode
Viterbi
Volumetric
Binary