How is direct binary FSK modulation generated?
BBy changing an oscillator’s frequency directly with a digital control signal
general pool
Subelement G8 question review
All 42 official questions with the exact winning phrase marked.
What is the name of the process that changes the phase angle of an RF signal to convey information?
BPhase modulation
What is the name of the process that changes the instantaneous frequency of an RF wave to convey information?
DFrequency modulation
What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?
BPhase modulation
What type of modulation varies the instantaneous power level of the RF signal?
DAmplitude modulation
Which of the following is characteristic of QPSK31?
DAll these choices are correct
Which of the following phone emissions uses the narrowest bandwidth?
ASingle sideband
Which of the following is an effect of overmodulation?
DExcessive bandwidth
What type of modulation is used by FT8?
A8-tone frequency shift keying
What is meant by the term “flat-topping,” when referring to an amplitude-modulated phone signal?
CSignal distortion caused by excessive drive or speech levels
What is the modulation envelope of an AM signal?
AThe waveform created by connecting the peak values of the modulated signal
What is QPSK modulation?
DModulation in which digital data is transmitted using 0-, 90-, 180- and 270-degrees phase shift to represent pairs of bits
What is a link budget?
CThe sum of transmit power and antenna gains minus system losses as seen at the receiver
What is link margin?
BThe difference between received power level and minimum required signal level at the input to the receiver
Which mixer input is varied or tuned to convert signals of different frequencies to an intermediate frequency (IF)?
BLocal oscillator
What is the term for interference from a signal at twice the IF frequency from the desired signal?
BImage response
What is another term for the mixing of two RF signals?
AHeterodyning
What is the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency?
DMultiplier
Which intermodulation products are closest to the original signal frequencies?
COdd-order
What is the total bandwidth of an FM phone transmission having 5 kHz deviation and 3 kHz modulating frequency?
D16 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?
B416.7 Hz
Why is it important to know the duty cycle of the mode you are using when transmitting?
BSome 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?
DIt results in the best signal-to-noise ratio
What is the relationship between transmitted symbol rate and bandwidth?
BHigher symbol rates require wider bandwidth
What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output?
CThe sum and difference
What process combines two signals in a non-linear circuit to produce unwanted spurious outputs?
AIntermodulation
Which of the following is an odd-order intermodulation product of frequencies F1 and F2?
C2F1-F2
Which digital mode is used as a low-power beacon for assessing HF propagation?
AWSPR
What part of a packet radio frame contains the routing and handling information?
CHeader
Which of the following describes Baudot code?
CA 5-bit code with additional start and stop bits
In an ARQ mode, what is meant by a NAK response to a transmitted packet?
ARequest retransmission of the packet
What action results from a failure to exchange information due to excessive transmission attempts when using an ARQ mode?
BThe connection is dropped
Which of the following narrow-band digital modes can receive signals with very low signal-to-noise ratios?
BFT8
Which of the following statements is true about PSK31?
BUpper case letters use longer Varicode bit sequences and thus slow down transmission
Which is true of mesh network microwave nodes?
BIf one node fails, a packet may still reach its target station via an alternate node
How does forward error correction (FEC) allow the receiver to correct data errors?
CBy transmitting redundant information with the data
How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?
DMark and space
Which type of code is used for sending characters in a PSK31 signal?
AVaricode
What is indicated on a waterfall display by one or more vertical lines on either side of a data mode or RTTY signal?
DOvermodulation
Which of the following describes a waterfall display?
CFrequency is horizontal, signal strength is intensity, time is vertical
What does an FT8 signal report of +3 mean?
CThe signal-to-noise ratio is equivalent to +3dB in a 2.5 kHz bandwidth
Which of the following provide digital voice modes?
DDMR, D-STAR, and SystemFusion