Transmission methods. Up to 18 miles

Transcription

1 AV Systems Design Twisted Pair and Fiber Optics Biju P. Pillai Sr. Technical Manager Extron Electronics

2 Objectives Video Signal Characteristics Analog and Digital Signal Characteristics Video Loss and Compensation Moving AV signals over data infrastructure Analog Video Solutions Coaxial Twisted Pair Fiber Twisted Pair in A/V Fiber in A/V

3 Transmission methods Up to 600 Coaxial Up to 1500 Twisted Pair Fiber Optic Up to 18 miles

4 Analog Video Formats High Res Video Can be either Low Res Video RGBHV = 5- Wire RGBS = 4- Wire RsGsBs/RGsB = 3- Wire Component = 3- Wire S-Video (Y-C) = 2- Wire Decoded Encoded

5 Analog Signal Types Low Resolution Video National Television Standards Committee (NTSC) 72 0 Field A Interlaced Field B Interlaced 52 5

6 Analog Signal Types High Resolution Video Advanced Television Systems Committee (ATSC) Video Electronics Standards Association (VESA) A wide variety of market driven resolutions o r 720 p 1920 x x i Satellite Rx o r Blu-ray 1680 x x 900

7 Electrical Characteristics of Cable Resistance Opposition to the flow of electrons Specification is given in Ohms / 1000 feet Appears as lack of brightness in the video image Capacitance Electrical charge a cable can hold Affects time it takes for cable to charge and discharge How fast can the signal turn off and on? Appears as loss of image sharpness

8 Analog Video Distance with Coax No defined distance limitation Not forced to follow good design practices Passive Plate 35 ~ ~ Signal gradually degrades but remains visible long into its degraded state 35 ~ ~ Extende r D

9 Cable Loss Artifacts Resistance and capacitance work together 12 To affect 100 Brightness Contrast Sharpness Quality of cable also impacts the amount of loss Limiting signal loss is ALWAYS better than compensation Better cable, less loss

10 How far can a video signal go? Distance limitations are based on: Frequency Pixel duration Type of cable being used Resistance Capacitance System capabilities Cumulative system bandwidth What is the content

11 Level control Video Compensation Compensates for long distances resistance Peaking control Compensates for high frequency loss Cable capacitance Multiple system components Controls are available on Interfaces, Line Drivers and some Distribution Amplifiers

12 Signal Loss and the Pixel Loss causes video to display poorly Loss affects Rise time (increases) Amplitude (decreases) Loss increases jitter If a pixel has no shelf then the display locks to a moving signal, hence shimmer

13 Digital Considerations

14 Digital Video Characteristics Synchronous Must transition at specific intervals determined by the clock Signal swing The difference between high and low values Clock period The minimum allowable time between transitions Digital Data Parameters

15 Analog vs. Digital With an analog signal the shape is important Amplitude = intensity Rise and fall times = sharpness With digital signals; Bit Error is what is important Can the receiving circuit properly identify a data bit as being high or low

16 Digital Video Signal Loss Cliff Effect Good Cliff Effect is unique to digital signaling Loss of Signal No Video Signal Quality LCD Monitor Acceptable Signal Level Bad Cable Length Analog Signal Digital Signal

17 The Eye Pattern An eye diagram is formed by repeated sampling of a digital signal The Eye Pattern is used to determine the likelihood of Bit Errors Good Signal Quality Bad Cable Length Digital Signal

18 Digital Video Characteristics Recovery Equalizers Used to restore cable losses Restores Level, Rise/Fall times Equalizers are in the first stage of a receiver circuit Equalizers do not remove jitter Into the Receiver After EQ circuit

19 Digital Video Characteristics Recovery Re Clocker SDI, HD SDI and DisplayPort Restores timing accuracy using an internal clock Reduces random and deterministic jitter Regeneration DVI and HDMI Cleans up timing using signals clock Reduces deterministic jitter but not random jitter Jitter into the Receiver EQ d & Re-Clocked

20 Twisted Pair AV Signal Transmission

21 AV signal delivery over Twisted Pair What is AV over Twisted Pair? Is this Network delivery? Is this Streaming?

22 AV signals over Twisted Pair This is NOT delivered through a network appliance! This is point to point signal delivery over Twisted pair cables Utilizes standard category rated cables Cannot be routed through powered network components

23 Why use Twisted Pair? Long Distance Transmission High resolution analog signals can be sent 2 to 3 times farther over twisted pair cable compared to coaxial cable Up to x12 00 Up to x12 00

24 Why use Twisted Pair? Smaller size cable Limited conduit space Requires less space Environmental impact Historical buildings (run externally) May eliminate the need to core or trench floor in 9.17 mm in mm in 6.09 mm MHR-5 RG6-5 Skew- Free Coax Coax Twisted Pair in 3 mm SM Simplex Fiber

25 Why use Twisted Pair? Improved noise immunity Audio and Video are run balanced so noise is cancelled out RFI EMI Twisted Pair Coax

26 Why use Twisted Pair? Use of existing cable infrastructure Many facilities will have unused preterminated twisted pair cable pulled throughout the building that the A/V Integrator can use Twisted pair cable can also be easier, faster and less expensive to terminate compared to coaxial cable Extron VGA Cable

27 TP integration into AV Compensating for long cable runs Level Peaking Compensating for different pair twists (lengths) Skew

28 Level Brightness loss due to cable resistance

29 Level Adjustment Restore signal level to 0.7 Volt To visually assess image quality Crosshatch Checkerboard H pattern Alternating pixel No Compensation With Compensation RGBHV Twisted Pair RGBHV Twisted Pair

30 Peaking Smearing and sharpness loss due to cable capacitance Low frequencies are compromised resulting in smearing High frequencies are rolled off resulting in loss of sharpness Normal H Pattern

31 Multi Stage Peaking Adjustment Recover rise time To visually assess image quality Crosshatch Checkerboard H pattern Alternating pixel With No Compensation RGBHV Twisted Pair RGBHV Twisted Pair

32 Skew Relates to twist ratio per pair Length of the conductors will vary between pairs twists twists

33 Skew Delay Propagation delay between each pair Maximum time difference between shortest and longest pair

34 Pixel Behavior Cable with skew delay of 0.25ns per meter At 30 meters => delay = 7.5ns 1024 x 60Hz 15 ns ½ pixel shift 1280 x 60Hz 8 ns 1 pixel shift Pixel Clock = 65 MHz Pixel Clock = 135 MHz

35 Effect of Delay Skew on displays with 1/2 pixel shift SUB- PIXELS PIXELS P1 P2 P3 Red Chan nel Green Chan nel Blue Chan nel Cloc k 0.7 V 0 V 0.7 V 0 V 0.7 V 0 V 5 V Digital Display CRT Monitor

36 Effect of Delay Skew on displays with 1 pixel shift SUB- PIXELS PIXELS P1 P2 P3 Red Chan nel Green Chan nel Blue Chan nel Cloc k 0.7 V 0 V 0.7 V 0 V 0.7 V 0 V 5 V Digital Display CRT Monitor

37 Skew delay compensation Skew free UTP cable No skew difference between video pairs No equalization needed Standalone Skew Compensation Up to 64ns Coax delay

38 No match! Network Compatibility Our signals can damage network hardware Some Twisted Pair products have large DC voltages Our signals are analog Network hardware is designed for digital signals

39 Mixing and Matching Twisted Pair products All manufacturers follow their own product design process Currently no A/V standard in Twisted Pair signal Transmission Date Edited

40 Matrix issues with Skew Multi Input to one out Skew equalization on each input Input Output Matrix

41 Matrix issues with Skew Multi Input to multi out Skew equalization becomes complex Matrix Input Output

42 Matrix System 2 - Remote Control Input Output Matrix Varying Distances

43 Point to Point Video TX / RX RGBHV / VGA C V, S Video Dual Mono audio Stereo Audio

44 Individual Cable Runs One source to multiple displays

45 Daisy Chain distribution One Source to Multiple Displays Looping from one display to the next

46 Fiber Optic AV Signal Transmission

47 Why use fiber? Immune to electrical interference Immune to EMI, RFI or lightning strikes No common group required No ground loops Coa x Power Line Receiver Bit errors Fibe r Receiver Coa x Receiver Bit errors Fibe r Receiver

48 Why use fiber? Smaller than copper cables Less weight and Cheaper to transport Higher density 216 fiber optical ribbon cable has same effective cross sectional area as two (2) CAT 6A cables

49 Why use fiber? Lower Energy Consumption Green building initiatives Approximately 20% of the energy required for a comparable copper based system Fewer/smaller cables equal better airflow in racks

50 Why use fiber? Low loss Capable of driving longer distances Cable Type Coax Attenuation Frequency dependent 100m 6.2dB Multi mode Single mode 1~6 db/km 0.1~0.6 db 0.2~0.4 db / Km 0.02~0.04dB

51 Benefits of Fiber in AV systems Secure transmission Resistant to ground loops Low Attenuation EMI/RFI Immunity Lightweight

52 Fiber Technologies Attenuation The loss of optical power caused by scattering and absorption. Based on governed standards Rated in db/km

53 Transmission Method Transmitters convert electrical to light energy Receivers convert light to electrical energy Two Types of Light sources LED Light Emitting Diode Multimode fiber cable LASER Light Amplification by Stimulated Emission of Radiation Singlemode and Multimode fiber cable Extron uses lasers in all products

54 Fiber Optic Cable Singlemode - long distances Core size 8 to 9 micrometers and transmits at 1310, 1550 nm Only allows one mode/path of light Singlemode Low losses typically 0.2 to 0.4 db/km Multimode - short distances fiber Core size typically 50 or 62.5 micrometers and transmits 850, 1300 nm Allows more than one mode/path of light Typical loss 1 to 6 db/km Multimode fiber

55 Fiber Attenuation Attenuation is the loss of light or signal power Extrinsic Splices Connectors End finishes Couplers Macrobends Microbends Intrinsic Absorption Scattering Macrobend

56 Converting AV / Control Signals to Optical Multiplexing of AV signals Time Division Multiplexing Higher Bandwidth Easier system Integration Wave Division Multiplexing Lower Bandwidth

57 Time Division Multiplexing Uses one Wavelength High bandwidth transmission Typically 4 6 Gbps Enables the use of a digital Fiber Optic switching and distribution system No need for de skew or retiming

58 Bandwidth Concerns Standard Resolution Aspect Ratio # Pixels Data Rate - MB/s Data Rate - Gbps QVGA 320x240 4:3 76, VGA 640x480 4:3 307, WVGA 853x480 16:9 409, SVGA 800x600 4:3 480, XGA 1024x768 4:3 786, HD 1280x720 16:9 921, WXGA 1368x768 16:9 1,050, SXGA 1280x1024 5:4 1,310, SXGA+ 1400x1050 4:3 1,470, UXGA 1600x1200 4:3 1,920, HD 1920x :9 2,073, QXGA 2048x1536 4:3 3,145, QSXGA 2560x2048 5:4 5,242, QUXGA 3200x2400 4:3 7,680,

59 Wave Division Multiplexing Uses Multiple wavelengths Information sent simultaneously Lower bandwidth transmission 1 2 Gbps Switching and distribution is typically not supported with CDWM

60 Sync PL L Clock Transmitter R A D 8 Bit - Red G A D 8 Bit - Green Multiplexer Optical Converter B A D 8 Bit - Blue Audio A D 2 x18 Bit Audio Level RS-232Translator Serial RS-232

61 Receiver Clock PL L Sync 8 Bit - Red D A R Optical Converter De- Multiplexer 8 Bit - Green D A G 8 Bit - Blue D A B 2 x18 Bit Audio D A Audio

62 Available Optical Power Budget Single Mode Transmitter power output SM. 5 dbm Receiver sensitivity SM. 18 dbm Optical Power Budget 5 dbm ( ) 18 dbm 13 db for Single Mode Multi Mode Transmitter power output SM. - 5 dbm Receiver sensitivity SM dbm Optical Power Budget Multi Mode - 5 dbm ( -) - 12 dbm db for

63 Mission critical information Command centers War rooms Call centers Crisis management Medical imaging

64 Secure, hazardous, and noisy environments Classified areas Briefing rooms Operations centers Hazardous environments Chemical plants Noisy environments Lighting grids Areas with heavy machinery

65 Questions