Element 8: Ship Radar Techniques

effective 6/25/2009

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8-C-20: Mixers

Figure 8C9

8-20C1: The diagram in Fig. 8C9 shows a simplified RADAR mixer circuit using a crystal diode as the first detector. What is the output of the circuit when no echoes are being received?

No output is developed.

60 MHz CW.

4095 MHz CW.

4155 MHz CW.



8-20C2: In the receive mode, frequency conversion is generally accomplished by a:

Crystal diode.

Tunable wave-guide section.

Pentagrid converter.

Ferrite device.



8-20C3: An RF mixer has what purpose in a RADAR system?

Converts a low-level signal to a different frequency.

Mixes the CW transmitter output to form pulsed waves.

Prevents microwave oscillations from reaching the antenna.

Combines audio tones with RF to produce the RADAR signal.



8-20C4: In a RADAR unit, the mixer uses a:

Silicon crystal or PIN diode.

Pentagrid converter tube.

Field-effect transistor.

Microwave transistor.



Figure 8A1

8-20C5: What component of a RADAR receiver is represented by block 49 in Fig. 8A1?

Crystal detector (the mixer).

Discriminator.

IF amplifier.

Klystron.



8-20C6: In a RADAR unit, the mixer uses:

PIN diodes and silicon crystals.

PIN diodes.

Boettcher crystals.

Silicon crystals.





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8-C-19: Receiving Systems
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Element 8: Ship Radar Techniques
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8-C-21: Local Oscillators