Practice Test Geeks(CMRT) Certified Marine Radar Technician Practice Test
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Signal Processing & Antenna Theory Flashcards

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

Read the first 7 Signal Processing & Antenna Theory flashcards as text

  1. In marine radar, rain clutter differs from sea clutter primarily because:

    Answer: Rain clutter is volumetric and can appear at any range within precipitation areas

    Rain clutter is volumetric, occurring wherever precipitation exists, unlike sea clutter which is surface-based and range-dependent.

  2. What is the significance of the radar ambiguity function?

    Answer: It describes a waveform's joint range and Doppler resolution and ambiguity performance

    The ambiguity function characterizes how well a radar waveform can simultaneously resolve targets in range and Doppler velocity.

  3. Which waveguide mode is the dominant mode used in rectangular waveguides for marine radar feeds?

    Answer: TE10

    The TE10 mode is the dominant mode in rectangular waveguides because it has the lowest cutoff frequency and propagates with the least loss.

  4. A radar system has a false alarm time of 10 minutes. If the detection threshold is lowered, the false alarm time will:

    Answer: Decrease, producing more false alarms per unit time

    Lowering the detection threshold allows more noise peaks to exceed it, increasing the false alarm rate and decreasing the mean time between false alarms.

  5. What is the function of a circulator in a marine radar transceiver?

    Answer: It routes the transmit pulse to the antenna and the receive echo to the receiver

    A circulator is a non-reciprocal device that directs transmit energy to the antenna and receive energy from the antenna to the receiver, protecting the receiver from transmit power.

  6. Aperture tapering (amplitude weighting) in antenna design is used to:

    Answer: Reduce sidelobe levels at the cost of slightly wider main beam

    Amplitude tapering reduces sidelobes by weighting edge elements less than center elements, but results in a slightly broader main beam and reduced gain.

  7. In coherent radar processing, what enables the Doppler frequency of a target to be measured?

    Answer: Phase coherence between successive transmitted pulses allows detecting inter-pulse phase changes

    Coherent processing maintains phase reference between pulses, allowing the Doppler-induced phase shift between returns to be measured as a frequency.