NAB Broadcasting Technology & Equipment 3

Question 1

What does the acronym EAS stand for in broadcasting?

Accepted Answer

Emergency Alert System

Answer

The Emergency Alert System (EAS) is the national public warning system that requires broadcasters to interrupt programming to broadcast emergency alerts.

Question 2

A broadcast engineer notices the video waveform monitor shows the luminance signal peaking at 110 IRE. What is the problem?

Accepted Answer

The signal is over-modulated and may cause illegal broadcast levels

Answer

Legal broadcast luminance levels must not exceed 100 IRE (with sync at -40 IRE); exceeding this causes over-modulation and FCC compliance issues.

Question 3

Which type of microphone element uses a thin metallic diaphragm whose capacitance changes with sound pressure?

Accepted Answer

Condenser (capacitor)

Answer

Condenser microphones use a charged capacitor whose capacitance varies with diaphragm movement, requiring phantom power or a battery to maintain the charge.

Question 4

What is the purpose of a 'gen-lock' signal in a broadcast facility?

Accepted Answer

Synchronize multiple video sources to a common timing reference

Answer

Gen-lock (genlock) synchronizes the horizontal and vertical timing of cameras and other video equipment to a common house sync signal, enabling glitch-free switching.

Question 5

In FM broadcasting, what is the maximum permissible frequency deviation for a monaural signal?

Accepted Answer

±75 kHz

Answer

The FCC specifies a maximum frequency deviation of ±75 kHz for FM broadcast stations, which corresponds to 100% modulation.

(NAB) National Association of Broadcasters Certification Practice Test

(NAB) National Association of Broadcasters Certification Practice Test

NAB Broadcasting Technology & Equipment 3