2.9 KiB
2.9 KiB
G8B – Frequency changing; bandwidths of various modes; deviation; intermodulation
- G8B01 (B)
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
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D. Beat frequency oscillator
- G8B02 (B)
What is the term for interference from a signal at twice the IF frequency from the desired signal?
- A. Quadrature response
- B. Image response
- C. Mixer interference
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D. Intermediate interference
- G8B03 (A)
What is another term for the mixing of two RF signals?
- A. Heterodyning
- B. Synthesizing
- C. Frequency inversion
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D. Phase inversion
- 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?
- A. Mixer
- B. Reactance modulator
- C. Balanced converter
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D. Multiplier
- G8B05 (C)
Which intermodulation products are closest to the original signal frequencies?
- A. Second harmonics
- B. Even-order
- C. Odd-order
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D. Intercept point
- G8B06 (D)
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
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D. 16 kHz
- 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?
- A. 101.75 Hz
- B. 416.7 Hz
- C. 5 kHz
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D. 60 kHz
- G8B08 (B)
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
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D. To prevent overmodulation
- G8B09 (D)
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
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D. It results in the best signal-to-noise ratio
- G8B10 (B)
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
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D. Bandwidth is half the symbol rate
- G8B11 (C)
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
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D. The arithmetic product
- G8B12 (A)
What process combines two signals in a non-linear circuit to produce unwanted spurious outputs?
- A. Intermodulation
- B. Heterodyning
- C. Detection
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D. Rolloff
- G8B13 (C)
Which of the following is an odd-order intermodulation product of frequencies F1 and F2?
- A. 5F1-3F2
- B. 3F1-F2
- C. 2F1-F2
- D. All these choices are correct