–1 vote
in E4-2020 by

A: A device that detects rotation of a control by interrupting a light source with a patterned wheel
B: A device that measures the strength of a beam of light using analog to digital conversion
C: A digital encryption device often used to encrypt spacecraft control signals
D: A device for generating RTTY signals by means of a rotating light source

1 Answer

0 votes
by (377 points)
I'm really not sure this knowledge is important to radio work, even for an extra.

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