CTS AV Signal Flow and Distribution 5 — Questions and Answers
Question 1: In HDBaseT signal distribution, which of the following is NOT carried over a single Cat cable?
- 4K video
- 100BaseT Ethernet
- USB 3.0 SuperSpeed data (Correct answer)
- Power over HDBaseT (PoH)
Correct answer: USB 3.0 SuperSpeed data
HDBaseT carries video, audio, Ethernet, control signals, and power (PoH), but USB 3.0 SuperSpeed is not part of the HDBaseT specification.
Question 2: Which term describes the condition where two identical audio signals are combined but one is 180° out of phase, resulting in signal cancellation?
- Phase distortion
- Polarity inversion cancellation (Correct answer)
- Common-mode rejection
- Summing null
Correct answer: Polarity inversion cancellation
Polarity inversion cancellation (phase cancellation) occurs when identical signals with reversed polarity are summed, causing destructive interference.
Question 3: A video signal is described as 1080i/60. What does the '60' represent in this context?
- 60 complete frames per second
- 60 fields per second (30 frames) (Correct answer)
- 60 Hz pixel clock frequency
- 60 Mbps bitrate
Correct answer: 60 fields per second (30 frames)
In interlaced notation, the number refers to fields per second; 1080i/60 delivers 60 fields (odd + even lines alternating), equating to 30 complete frames per second.
Question 4: A system designer wants to send a 4K HDR signal with Dolby Atmos audio over a network. Which specification must the HDMI cable and switches support?
- HDMI 1.4b
- HDMI 2.0a
- HDMI 2.1 (Correct answer)
- HDMI 1.3
Correct answer: HDMI 2.1
HDMI 2.1 supports 4K/120Hz, HDR10+, and the Enhanced Audio Return Channel (eARC) required for Dolby Atmos object-based audio.
Question 5: In a balanced audio line, the shield of the cable is connected to pin 1 of an XLR connector. What is the shield's primary purpose?
- Carry the positive audio signal
- Provide a return path for phantom power
- Reject electromagnetic interference by grounding noise (Correct answer)
- Balance the impedance between hot and cold conductors
Correct answer: Reject electromagnetic interference by grounding noise
The shield surrounds the inner conductors and is grounded to divert induced electromagnetic interference away from the audio signal.
Question 6: Which display technology characteristic makes it MOST susceptible to interference from strong magnetic fields near the display?
- LCD (Liquid Crystal Display)
- CRT (Cathode Ray Tube) (Correct answer)
- OLED (Organic Light Emitting Diode)
- DLP (Digital Light Processing)
Correct answer: CRT (Cathode Ray Tube)
CRT displays use electron beams steered by magnetic deflection coils, making them highly vulnerable to distortion from external magnetic fields.
Question 7: A technician must verify that an HDMI signal is being received correctly before it reaches the display. Which tool is BEST suited for this task?
- Cable toner and probe
- HDMI signal analyzer/pattern generator (Correct answer)
- Digital multimeter
- Network packet sniffer
Correct answer: HDMI signal analyzer/pattern generator
An HDMI signal analyzer or pattern generator can inject and decode HDMI test patterns, verify EDID/HDCP handshakes, and measure signal timing parameters.
CTS AV Signal Flow and Distribution 5
In HDBaseT signal distribution, which of the following is NOT carried over a single Cat cable?