Practice Test Geeks(GROL) General Radiotelephone Operator License Practice Test
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Receivers and Transmitters Flashcards

7 cards from real GROL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Receivers and Transmitters flashcards as text

  1. What is the function of a buffer amplifier stage in a transmitter?

    Answer: To isolate the master oscillator from load variations that could cause frequency pulling

    A buffer amplifier presents a stable, high-impedance load to the oscillator so that changes in subsequent stages do not pull the oscillator off frequency.

  2. At 100% amplitude modulation, what percentage of total transmitted power is contained in the carrier?

    Answer: 66.7%

    At 100% modulation, each sideband carries 25% of the carrier power, so total power = 1.5 × Pc; the carrier fraction is 1/1.5 ≈ 66.7%.

  3. A frequency multiplier stage in an FM transmitter:

    Answer: Multiplies both the carrier frequency and the frequency deviation by the same integer factor

    Frequency multipliers multiply every frequency component, so both the center frequency and the peak deviation increase by the same factor.

  4. What is the primary purpose of the low-pass filter at the output of a transmitter?

    Answer: To suppress harmonic and spurious emissions before the signal reaches the antenna

    The low-pass filter passes the fundamental transmit frequency but attenuates harmonics and other spurious products that could interfere with other services.

  5. A final RF amplifier has a DC input of 100 W and an RF output of 60 W. What is its efficiency?

    Answer: 60%

    Efficiency = (RF output / DC input) × 100% = (60 W / 100 W) × 100% = 60%.

  6. In an SSB transmitter, the carrier is suppressed using:

    Answer: A balanced modulator that cancels the carrier through circuit symmetry

    A balanced modulator produces a double-sideband suppressed-carrier (DSBSC) output by exploiting circuit balance to cancel the carrier while passing both sidebands.

  7. Automatic Level Control (ALC) in an SSB transmitter is used to:

    Answer: Prevent overdrive and excessive peak power by reducing gain when signal peaks exceed a threshold

    ALC reduces the drive to the final amplifier on voice peaks, preventing flat-topping, IMD, and splatter into adjacent channels.