81 lines
3.0 KiB
Markdown
81 lines
3.0 KiB
Markdown
G8B – Frequency changing; bandwidths of various modes; deviation; intermodulation
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- [[G8B01]] (B)
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Which mixer input is varied or tuned to convert signals of different frequencies to an intermediate frequency (IF)? #card
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- A. Image frequency
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- B. Local oscillator
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- C. RF input
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- D. Beat frequency oscillator
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- [[G8B02]] (B)
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What is the term for interference from a signal at twice the IF frequency from the desired signal? #card
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- A. Quadrature response
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- B. Image response
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- C. Mixer interference
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- D. Intermediate interference
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- [[G8B03]] (A)
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What is another term for the mixing of two RF signals? #card
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- A. Heterodyning
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- B. Synthesizing
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- C. Frequency inversion
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- D. Phase inversion
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- [[G8B04]] (D)
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What is the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency? #card
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- A. Mixer
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- B. Reactance modulator
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- C. Balanced converter
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- D. Multiplier
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- [[G8B05]] (C)
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Which intermodulation products are closest to the original signal frequencies? #card
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- A. Second harmonics
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- B. Even-order
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- C. Odd-order
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- D. Intercept point
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- [[G8B06]] (D)
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What is the total bandwidth of an FM phone transmission having 5 kHz deviation and 3 kHz modulating frequency? #card
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- A. 3 kHz
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- B. 5 kHz
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- C. 8 kHz
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- D. 16 kHz
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- [[G8B07]] (B)
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What is the frequency deviation for a 12.21 MHz reactance modulated oscillator in a 5 kHz deviation, 146.52 MHz FM phone transmitter? #card
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- A. 101.75 Hz
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- B. 416.7 Hz
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- C. 5 kHz
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- D. 60 kHz
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- [[G8B08]] (B)
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Why is it important to know the duty cycle of the mode you are using when transmitting? #card
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- A. To aid in tuning your transmitter
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- B. Some modes have high duty cycles that could exceed the transmitter’s average power rating
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- C. To allow time for the other station to break in during a transmission
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- D. To prevent overmodulation
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- [[G8B09]] (D)
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Why is it good to match receiver bandwidth to the bandwidth of the operating mode? #card
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- A. It is required by FCC rules
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- B. It minimizes power consumption in the receiver
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- C. It improves impedance matching of the antenna
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- D. It results in the best signal-to-noise ratio
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- [[G8B10]] (B)
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What is the relationship between transmitted symbol rate and bandwidth? #card
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- A. Symbol rate and bandwidth are not related
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- B. Higher symbol rates require wider bandwidth
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- C. Lower symbol rates require wider bandwidth
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- D. Bandwidth is half the symbol rate
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- [[G8B11]] (C)
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What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output? #card
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- A. The ratio
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- B. The average
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- C. The sum and difference
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- D. The arithmetic product
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- [[G8B12]] (A)
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What process combines two signals in a non-linear circuit to produce unwanted spurious outputs? #card
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- A. Intermodulation
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- B. Heterodyning
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- C. Detection
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- D. Rolloff
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- [[G8B13]] (C)
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Which of the following is an odd-order intermodulation product of frequencies F1 and F2? #card
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- A. 5F1-3F2
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- B. 3F1-F2
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- C. 2F1-F2
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- D. All these choices are correct
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