Sub Element G8: Signals and Emissions Flashcards
Which mixer input is varied or tuned to convert signals of different frequencies to an intermediate frequency (IF)?
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?
Image response
What is another term for the mixing of two RF signals?
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?
Multiplier
G8B05 (D) What is the approximate bandwidth of a PACTOR-III signal at maximum data rate?
2300 Hz
What is the total bandwidth of an FM phone transmission having 5 kHz deviation and
3 kHz modulating frequency?
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?
416.7 Hz
Why is it important to know the duty cycle of the mode you are using when transmitting?
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?
It results in the best signal-to-noise ratio
What is the relationship between transmitted symbol rate and bandwidth?
Higher symbol rates require wider bandwidth
What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output?
The sum and difference
What process combines two signals in a non-linear circuit or connection to produce unwanted spurious outputs?
Intermodulation
On what band do amateurs share channels with the unlicensed Wi-Fi service?
2.4 GHz
Which digital mode is used as a low-power beacon for assessing HF propagation?
WSPR
What part of a packet radio frame contains the routing and handling information?
Header
