CBT Equipment & Troubleshooting 2

Question 1

A transmitter's VSWR suddenly spikes to 3:1. What is the FIRST corrective action a broadcast technologist should take?

Accepted Answer

Inspect the transmission line and antenna for faults

Answer

A high VSWR indicates an impedance mismatch, most commonly caused by a transmission line or antenna fault that must be located and corrected.

Question 2

Which test instrument is used to measure the frequency response of an audio circuit?

Accepted Answer

Audio signal generator and analyzer

Answer

An audio signal generator sweeps frequencies while an analyzer measures the output level, producing a frequency response curve.

Question 3

An FM exciter's stereo pilot tone is missing. Which subsystem should the technologist check first?

Accepted Answer

Stereo generator (composite encoder)

Answer

The 19 kHz stereo pilot is generated by the stereo composite encoder; its absence points to a fault in that subsystem.

Question 4

A broadcast engineer notices audio is present on a video feed but the waveform monitor shows the video level is 120 IRE. What problem does this indicate?

Accepted Answer

Video is clipped above white level (superwhite)

Answer

100 IRE is standard white; a level of 120 IRE means the video exceeds the white clip level, which can cause issues in downstream processing.

Question 5

What does an Optical Time-Domain Reflectometer (OTDR) measure in a fiber optic plant?

Accepted Answer

Location and magnitude of losses and reflections along a fiber

Answer

An OTDR sends light pulses down the fiber and analyzes backscatter to pinpoint splices, connectors, breaks, and their associated losses.

(CBT) Certified Broadcast Technologist Practice Test

(CBT) Certified Broadcast Technologist Practice Test

CBT Equipment & Troubleshooting 2