NAB Technology & Digital Tools 3 — Questions and Answers
Question 1: Which multiplexing scheme is used by ATSC 3.0 (NextGen TV) to improve spectral efficiency compared to ATSC 1.0?
- 8-VSB
- OFDM (Correct answer)
- QAM-64
- CDMA
Correct answer: OFDM
ATSC 3.0 uses OFDM (Orthogonal Frequency Division Multiplexing), which offers superior multipath rejection and enables mobile reception, unlike the 8-VSB used in ATSC 1.0.
Question 2: A station's master control operator notices audio levels are riding at -10 dBFS consistently. What is the likely result on air?
- Audio that is too loud and distorted
- Audio that is too quiet for viewers (Correct answer)
- No audible difference compared to 0 dBFS
- Automatic loudness normalization kicks in only above -6 dBFS
Correct answer: Audio that is too quiet for viewers
Operating 10 dB below full scale means the audio will sound noticeably quieter than properly leveled content, degrading the viewer experience.
Question 3: What is the function of a frame synchronizer in a broadcast facility?
- Converts analog signals to digital
- Aligns incoming video to the facility's house sync (Correct answer)
- Compresses video for transmission
- Monitors signal quality for compliance
Correct answer: Aligns incoming video to the facility's house sync
A frame synchronizer buffers incoming video and re-clocks it to match the facility's master sync, preventing frame tears when switching between asynchronous sources.
Question 4: Which protocol is the industry standard for low-latency contribution feeds from remote locations to a broadcast facility over the internet?
- FTP
- SRT (Secure Reliable Transport) (Correct answer)
- HTTP Live Streaming (HLS)
- RTSP
Correct answer: SRT (Secure Reliable Transport)
SRT (Secure Reliable Transport) is an open-source protocol designed for reliable, low-latency video transport over unpredictable public internet connections.
Question 5: In a modern newsroom, what does the term 'MOS' refer to?
- Master Output Switch
- Media Object Server (Correct answer)
- Modular Output System
- Metadata Optimization Standard
Correct answer: Media Object Server
MOS (Media Object Server) is a protocol that enables communication between newsroom computer systems (NCS) and media production equipment like video servers.
Question 6: What is the purpose of closed captioning Line 21 data in analog NTSC broadcasts?
- Carrying teletext magazine services
- Embedding caption text in the vertical blanking interval (Correct answer)
- Synchronizing audio tracks
- Transmitting emergency alert signals
Correct answer: Embedding caption text in the vertical blanking interval
Line 21 of the NTSC vertical blanking interval (VBI) carries closed caption data encoded as two bytes per field, invisible to viewers but decoded by caption-capable televisions.
Question 7: A facility upgrades from HD-SDI (1.485 Gbps) to 12G-SDI. What is the primary benefit of 12G-SDI?
- Longer cable runs than HD-SDI
- Single-cable transport of 4K UHD video at up to 60fps (Correct answer)
- Built-in IP encapsulation
- Lossless audio compression
Correct answer: Single-cable transport of 4K UHD video at up to 60fps
12G-SDI carries 4K UHD video over a single coaxial cable at up to 60 frames per second, eliminating the quad-link HD-SDI workaround previously required for 4K.
NAB Technology & Digital Tools 3
Which multiplexing scheme is used by ATSC 3.0 (NextGen TV) to improve spectral efficiency compared to ATSC 1.0?