SUBELEMENT G8 – SIGNALS AND EMISSIONS

Question 1

G8A01 (B)

How is an FSK signal generated?

Answer 1

B. By changing an oscillator’s frequency directly with a digital control signal

Question 2

G8A02 (B)

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

Answer 2

B. Phase modulation

Question 3

G8A03 (D)

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

Answer 3

D. Frequency modulation

Question 4

G8A04 (B)

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

Answer 4

B. Phase modulation

Question 5

G8A05 (D)

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

Answer 5

D. Amplitude modulation

Question 6

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

Answer 6

C. Available transmitter power can be used more effectively

Question 7

G8A07 (A)

Which of the following phone emissions uses the narrowest bandwidth?

Answer 7

A. Single sideband

Question 8

G8A08 (D)

Which of the following is an effect of overmodulation?

Answer 8

D. Excessive bandwidth

Question 9

G8A09 (B)

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

Answer 9

B. Transmit audio or microphone gain

Question 10

G8A10 (C)

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

Answer 10

C. Signal distortion caused by excessive drive

Question 11

G8A11 (A)

What is the modulation envelope of an AM signal?

Answer 11

A. The waveform created by connecting the peak values of the modulated signal

Question 12

G8B01 (A)
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?

Answer 12

A. Mixer

Question 13

G8B02 (B)
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?

Answer 13

B. Image response

Question 14

G8B03 (A)

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

Answer 14

A. Heterodyning

Question 15

G8B04 (D)
What is the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency?

Answer 15

D. Multiplier

Question 16

G8B05 (D)

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

Answer 16

D. 2300 Hz

Question 17

G8B06 (D)

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

Answer 17

D. 16 kHz

Question 18

G8B07 (B)
What is the frequency deviation for a 12.21 MHz reactance modulated oscillator in a 5 kHz deviation, 146.52 MHz FM phone transmitter?

Answer 18

B. 416.7 Hz

Question 19

G8B08 (B)

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

Answer 19

B. Some modes have high duty cycles which could exceed the transmitter’s average power rating.

Question 20

G8B09 (D)

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

Answer 20

D. It results in the best signal to noise ratio

Question 21

G8B10 (B)

What is the relationship between transmitted symbol rate and bandwidth?

Answer 21

B. Higher symbol rates require wider bandwidth

Question 22

G8C01 (B)

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

Answer 22

B. JT9 and JT65

Question 23

G8C02(A)

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

Answer 23

A. The number varies

Question 24

G8C03 (C)

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

Answer 24

C. Header

Question 25

G8C04 (C)

Which of the following describes Baudot code?

Answer 25

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

Question 26

G8C05 (A)

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

Answer 26

A. The receiver is requesting the packet be retransmitted

Question 27

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

Answer 27

B. The connection is dropped

Question 28

G8C07 (B)

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

Answer 28

B. It requests the packet be retransmitted

Question 29

G8C08 (B)

Which of the following statements is true about PSK31?

Answer 29

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

Question 30

G8C09 (A)

What does the number 31 represent in “PSK31”?

Answer 30

A. The approximate transmitted symbol rate

Question 31

G8C10 (C)

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

Answer 31

C. By transmitting redundant information with the data

Question 32

G8C11 (D)

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

Answer 32

D. Mark and Space

Question 33

G8C12 (A)

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

Answer 33

A. Varicode