視訊系統概論及量測

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視訊系統概論及量測

  1. 1. µø°T¨t²Î·§½×¤¶q´úÀ³¥1
  2. 2. Seminar Agenda • Basic of Analog baseband video signal • Basic of Digital baseband Video signal • Demo : Measure analog & SDI Video signal by VM700T • DTV (Digital Television Video) Introduction and Theory • Digital Television Video SD/HD Testing2
  3. 3. Basics of Analog Video3
  4. 4. Class Content • Additive Color System • Raster Scan Concepts • Analog Component Signals • Analog Composite Signals • Test Equipment • Testing Concepts • List of Additional Study Material4
  5. 5. Additive Color System5
  6. 6. Additive Color System Different Luminance ( «G«× ) ( no chrominance ) ©ú«G¤Æ«×ÅÜ Chrominance (±m«× ) with different Luminance ( same hue ¦â¬Û & saturation ¹¡©M«× ±m«×ÅÜ¤Æ Chrominance with different saturation ¹¡©M«¤Æ×ÅÜ ( same luminance & hue ) Chrominance with different hue ( same luminance & saturation ) ¦â¬ÛÅܤÆ6
  7. 7. Class Content • Additive Color System • Raster Scan Concepts • Analog Component Signals • Analog Composite Signals • Test Equipment • Testing Concepts • List of Additional Study Material7
  8. 8. Camera Scanning Patterns Electron Gun Horizontal Retrace Video Signal Active Video8
  9. 9. Camera Interlace Scanning Patterns A B C D 1 3 2 4 5 6 Odd lines in Inactive lines in Even lines in Inactive lines in 1st vertical trace. 1st vertical retrace. 2nd vertical trace. 2nd vertical retrace. 625 - 1st Field = 312.5 Lines (25/sec) 625 - 2nd Field = 312.5 Lines (25/sec) 525 - 1st Field = 262.5 Lines (30/sec) 525 - 2nd Field = 262.5 Lines (30/sec) 625 - Frame = 625 Lines (25Hz) 525 - Frame = 525 Lines (30Hz) 525 = North American 625 = Europe and Most of the World9
  10. 10. Camera Scanning Patterns • Vertical Resolution – 525 horizontal lines per picture. (North America) – 625 horizontal lines per picture. (Most of world) • Vertical Scan Rate – Scan at least 48 times per second to reduce flicker. – 525 or 625 lines at 48 times per second difficult to achieve. • Interlaced Scan – Show all odd lines one time, all even lines next. – Field – 525 - ~60 Fields – 625 - 50 Fields – Frame – 525 - ~30 Frames – 625 - 25 Frames10
  11. 11. Class Content • Additive Color System • Raster Scan Concepts • Analog Component Signals • Analog Composite Signals • Test Equipment • Testing Concepts • List of Additional Study Material11
  12. 12. Television Transmission Red Light Signal Blue Light Signal Green Light Signal Color Camera Color Transmission System Receiver Red Light Signal Blue Light Signal Green Light Signal12
  13. 13. Analog Component Signals13
  14. 14. Component RGB WHT YEL CYN GRN MGT RED BLU BLK +700 mV CHANNEL 1 GREEN 0 mV -300 mV +700 mV • Defined by SMPTE CHANNEL 2 BLUE 0 mV • +700 mV max value -300 mV • Each channel is 4 MHz • Sync pulse on each +700 mV channel CHANNEL 3 RED 0 mV -300 mV14
  15. 15. Y, B-Y, R-Y Color Bars +714 mV WHT (700 mV) YEL CYN GRN CHANNEL 1 MGT Y* RED (Y) BLU BLK 0 mV -286 mV (-300 mV) +636 mV • Y - Luminance (+620 mV) CHANNEL 2 B-Y* (U) 0 mV • B-Y (U) -636 mV (-620 mV) • R-Y (V) +500 mV (+490 mV) 0 mV CHANNEL 3 -500 mV R-Y* (-490 mV) (V) * Derived from 714 mV RGB signals (Derived from 700 mV RGB signals- PAL ref burst values not shown)15
  16. 16. Component Vectorscope Display • Gives X/Y R M display of Y R-Y (V) and R-Y or V B-Y (U) B chrominance G CY components Tek B-Y or U16
  17. 17. Component Measurement • Bowtie Measurement Component Test Signal Generator CH1 CH2 CH3 – System Hook Up – Test Signals – CH 1 is 500 kHz sinewave Component Signal Waveform Monitor CHs 2 and 3 are CH1 CH2 CH3 502 kHz sinewaves – Resultant Waveforms – If the signals are timed and of the same amplitude, the Bowtie waveform results17
  18. 18. Component Measurement • Bowtie Measurement – Purpose – Compares the amplitude and timing of the three component signals – Test Signals CH1 CH2 CH3 – Channel 1 is 500 kHz sinewave. Test Signals Channels 2 and 3 are 502 kHz sinewaves – Resultant Waveforms – If the signals are timed and of the same amplitude, the Bowtie CH1-2 CH1-3 waveform results Resultant Waveforms18
  19. 19. Class Content • Additive Color System • Raster Scan Concepts • Analog Component Signals • Analog Composite Signals • Test Equipment • Testing Concepts • List of Additional Study Material19
  20. 20. Component to Composite +714 mV WHT (700 mV) YEL CYN GRN CHANNEL 1 MGT Y* RED (Y) BLU BLK 0 mV Composite -286 mV (-300 mV) +636 mV (+620 mV) CHANNEL 2 B-Y* 0 mV (U) -636 mV (-620 mV) QAM Modulator +500 mV (+490 mV) 0 mV CHANNEL 3 -500 mV R-Y* (-490 mV) (V) * Derived from 714 mV RGB signals (Derived from 700 mV RGB signals- PAL ref burst values not shown)20
  21. 21. NTSC Color Encoding Y S Adder Transmitter Matrix R-Y C 90 Degree R-Y C Phase Shift Modulator -27 Offset =Yellow o B-Y 3.579545MHz Subcarrier B-Y Oscillator Modulator21
  22. 22. Luminance and Chrominance 100 100 80 80 60 60 40 40 20 20 0 0 -20 -20 -40 -40 Luminance Chrominance22
  23. 23. Transmitted NTSC Color Burst 100 80 60 Color 40 Breezeway Burst 20 0 -20 -40 Tek Front Porch H Sync Back Porch Pulse23
  24. 24. Waveform Monitor NTSC Signal Peak Active Picture White 100 .714V 100 IRE 80 60 Setup Level 40 53.5mV 7.5 IRE 20 0 0 Blanking 0V, 0 IRE -20 -40 Sync Tip Tek -.286V -40 IRE Horizontal Sync Pulse Horizontal Blanking Interval24
  25. 25. Transmitted NTSC Color Burst Color Burst Local Color oscillator frequency and phase based on the color burst of input signal25
  26. 26. NTSC Receiver Luminance and Chrominance Decoding RF, IF and S Video Y Detector R Amplifier Circuirts B-Y Matrix G R-Y B Chrominance Filter and Amplifier Color burst C B-Y Demodulator 3.579545MHz R-Y 90 Degree Demodulator Subcarrier Phase Shift Oscillator26
  27. 27. NTSC - Not Really 60 Fields Per Second • North America uses NTSC and the 525 scan rate with is suppose to be 30 Frames/60 Fields. • NTSC field and frame rate is actually: – 29.97 Frames per Second – 59.94 Fields per Second • Why these weird numbers??????27
  28. 28. NTSC - Not Really 60 Fields Per Second Luminance (Y) Chrominance Sound Carrier Carrier Carrier .75 0 1.0 2.0 3.0 3.58 4.0 4.2 4.5 MHz • Changed field/frame rate to correct audio distortion caused by color carrier.28
  29. 29. Broadcast Standards • The table in the notes section below shows several broadcast standards: – Code – Number of frames – Number of scan lines – Frequency band use – Sound offset • Codes B, G and M are most commonly used29
  30. 30. Broadcast Standards Name Field/Frame Stds Encoding Scan Subcarrier Aspect Rate Org System Lines Frequency Ratio NTSC 29.97/59.94 EIA NTSC 525 3.58MHz 4:3 PAL-M 29.97/59.94 EIA PAL 525 3.58MHz 4:3 SECAM-M 29.97/59.94 EIA SECAM 525 ?.??MHz 4:3 PAL 25/50 ITU PAL 625 4.43MHz 4:3 SECAM 25/50 ITU SECAM 625 4.25MHz 4:3 4.40MHz PALplus 25/50 ITU PAL 625 4.43MHz 4:330
  31. 31. MEASUREMENTS31
  32. 32. Test Equipment • Waveform Monitor – Special oscilloscope that has been optimized for video signals – 75 Ohm Termination – Passive Loop Through – Optimized TV frame, Field, Line Triggering – Optimized Graticule – Optimized Frequency Response – Line Select Capability • Vectorscope – Shows the resulting colors generated by the color signals • Test Signal Generator – Video and audio signal generation capability32
  33. 33. Measurement Categories 1. Video Amplitude and Time Measurements 2. SCH Phase (SubCarrier to Horizontal) 3. Linear Distortions 4. Non-linear Distortions 5. Noise33
  34. 34. NTSC Luminance and Chrominance • QAM 3.58 MHz color information mixed with the luminance. • This is the display for 100 the color bar test 80 signal. 60 40 20 0 0 -20 -40 Tek34
  35. 35. Video Amplitude and Time Measurements (Amplitude) Composite 525 Format Signal Levels Luminance (Y) Peak White 100 .714V 100 IRE 80 60 Setup Level 40 53.5mV 7.5 IRE 20 0 Blanking 0V, 0 IRE -20 -40 Sync Tip Tek -.286V -40 IRE Horizontal Sync Pulse Horizontal Blanking Interval35
  36. 36. Composite 625 Format Signal Levels Luminance (Y) Peak White 100 .700V 80 60 40 20 Blanking 0 0V -20 -40 Sync Tip Tek -.300V Horizontal Sync Pulse Horizontal Blanking Interval36
  37. 37. Chrominance & Luminance Chrominance : refers to the color information in a TV picture. includes Hue and Saturation Luminance : represents brightness, or the amount of light in the picture. In color system it is obtained as a weighted sum Y=.3R+.59G+.11B of the R,G,& B signals Luminance Saturation Chrominance Hue37
  38. 38. NTSC Vectorscope Display • Displays phase of the R-Y (NTSC) chrominance signals. • X/Y display of R M R-Y and B-Y Y components. -(B-Y) B-Y (NTSC) (NTSC) B Y Y G CY Tek Y Y Phase of -(R-Y) (NTSC) the Color Subcarrier38
  39. 39. Video Amplitude and Time Measurements (Time) ¡@ Measurements of horizontal and vertical synchronization pulse widths ¡@ Both RS-170A and FCC provide recommended limits ¡@ Cause the picture breakup ¡@ Any composite signal containing horizontal, vertical and burst sync. BLANKING 10.49¡@ SEC ~ 11.49¡@ SEC 10.9¡@ ¡@ SEC0.2 ¡@ SEC 9.22¡@ SEC MIN. 9.4¡@ ¡@ SEC0.1¡@ SEC 7.94¡@ SEC MAX. 1.27¡@ SEC 7.8¡@ SEC MIN. 100IRE 714mV FRONT REF BURST COLOR WHITE 0.254¡@ SEC 0.254¡@ SEC PORCH BACK MAX. MAX. 2.5¡@ SEC 4 IRE 1.5¡@ SEC BREEZWAY PORCH 90% TO 110% REF BLACK 0 IRE ¡@ +.1¡@ SEC0.6¡@ SEC 1.6¡@ SEC OF M SYNC LEVEL -4 IRE AMPLITUDE SYNC 7.5IRE 4 IRE 4.7¡@ SEC  ¡@ 4 IRE 40IRE 0.1 ¡@ SEC 8 TO 11 BLANKING 20IRE LEVEL 0.38¡@ SEC CYCLES 40IRE REF SYNC MIN. 286mV AMPLITUDE -36 IRE -40 IRE RS-170A Horizontal Pulse FCC39
  40. 40. SCH Phase (SubCarrier to Horizontal) ¡@ Timing relationship between the 50 % point of the leading edge of sync. and the zero crossings of the reference subcarrier ¡@ RS-170A SCH Phase within + 40 deg. Modern facilities < few deg. ¡@ Two or more sources are combined or sequentially switched - ¡@ Any signal with both sync and burst Phase =0.0Deg Zero crossing 50% Leading edge point40
  41. 41. Linear Distortions Frequency Response 0.5 1.25 2.0 3.0 3.58 4.1 MHz • Linear Distortions 4 8 10 14 16 18 Cycles – Definition: – Waveform distortions that are independent of signal amplitude are referred to as linear distortions. – Example: – Frequency Response - Higher frequency signal components (such as the color information) are attenuated.41
  42. 42. NonLinear Distortion Measurements Differential Phase and Gain • Purpose – Checks to see if either the chrominance phase or gain is affected by luminance level changes. • Test Signals – Modulated Five Step Staircase42
  43. 43. Noise Measurement Signal to Noise Ratio ( S/N or SNR )43
  44. 44. STANDARDS  No standards ,Depends on governments and experiences  Timing and Amplitude ¡@ EIA RS-170A ¡@ FCC73.699 Diagram#6  Distortions ¡@ NTC-7 ¡@ RS-250 (EIA-250C)44
  45. 45. 1740A/50A/60 Combination Waveform Monitors/Vectorscopes45
  46. 46. WVR500 Waveform/Vector Rasterizer • Application: Studio applications where space is at a premium. Signal is monitored at point of use and display is routed to a convenient picture monitor. • Customer: Production studios, house and remote monitoring systems, video training.46
  47. 47. VM700T Video Measurement Set • Automated Video Measurement Set • Video Parametric Testing on Test Patterns – NTSC (525/59.94i) Option 1 – PAL (625/50i) Option 11 – Component (RGB/YPbPr 525/625) Option 30 – Audio (Analog) Option 40/41 – SDI (143/270/360Mbs) Option 1S47
  48. 48. Manual Mode Waveform Monitor48
  49. 49. Manual Mode Vectorscope49
  50. 50. Manual Mode Picture50
  51. 51. Measure Mode Screen In /nvram0/Executable~Files/Video~Measurements Bar Bounce Burst LineTime Frequency ChromLum Chrominance Chrominance GainDelay AMPM FreqResp Chrominance ColorBar DGDP NonLinearity GroupDelay H_Blank H_Timing Sin X/X ICPM Jitter Jitter Audio Diags Video Previous Leave Options Selection Directory51
  52. 52. VmtWin© Software: PC Remote Control Software for the VM700T • Access and Remote control the measurement capabilities of the VM700T • Windows based interface for simple, intuitive PC control • Manual or full automatic screen capture and display of VM700T graphics. • Capability to remotely create, edit and run user defined functions • Multiple connection capabilities: Direct RS 232, Network via Serial Server, or RS 232 with modem • Available as a free download from the Tektronix Web site52
  53. 53. TG2000 Multi-Format TV Signal Generator• TG2000 Modules – HDVG1/HDTV Digital Video Generator – 14 Formats of HDTV SDI signal generation – 8 Channels of Embedded Audio support – AVG1/Analog Video Generator – NTSC, PAL, PAL-M, PAL-N, SECAM, Y/By/Ry, R/G/B, Beta-Cam and other major formats support – AWVG1/Analog Wide-band Video Generator – 525/625/HDTV and other wide-band signal support – Moving Zone-Plate Signal with variable parameter
  54. 54. TG2000 General• TG2000 Modules – DVG1/Digital Video Generator – 525/625-270MHz, 525/625-360MHz, 525-143MHz SDI and Parallel Digital Signals generation – SDI Stress Test (Option S1) – Variable Jitter, Amplitude, Through-rate and Rise/Fall Time of SDI signal – High Level Embedded Audio Support – AGL1/Analog GenLock – Adds GenLock capability to TG2000 – Lock to NTSC/PAL, CW (Continuous Wave)
  55. 55. SDP2000 Basic• SDP2000 – Signal Generation Tool for TG2000 – Works on MS-Windows (95, 98, NT) – Huge Test Signal Libraries for TG2000 Modules – Powerful set of Waveform Functions – Easy to use Editing Features
  56. 56. TG700 Multiformat Generator – AGL7 • Built for flexibility and upgradability Analog GenLock module – AG7 • Consists of mainframe (TG700) Audio Generator module Holds up to 4 modules per frame – ATG7 Analog Test Generator module – AVG7 Analog Video Generator module – AWVG7 Analog WideBand Video Generator module – BG7 Black Generator module – DVG7 SDTV Generator module – HDVG7 HDTV Generator module56
  57. 57. ATG7 Analog Test Generator Module • Four Independent Outputs – NTSC/PAL Analog Test Signals – 2 Black Bursts – BARS with ID TEXT • ID Text Overlay – ID Text overlay for Test Signal and Color Bar (1 Row x 18 Characters) • Output Formats – NTSC/PAL Independent selection for 4 outputs – Timing Pulse output (1Vpeak to peak) • Output Timing – Independent Timing adjustment with Full Color Frame range57
  58. 58. AVG7 Analog Video Generator Module 4 Analog Test Signal 0NTSC/PAL analog composite signal 0525/625 analog component signal 0APL and Bounce 4 High Quality Test Signal Generator 03 channel with 12 bits, 27 MHz clock 4 Frame Picture Feature (TG700 with Option FP) 0Create PIC file from Windows BMP 4 Active Picture Scroll Pr Pb YComposite Composite Composite 0For both test signals and frame picturesComposite C Y 4 Overlay Support 0Logo, ID text and circle overlay 4 Output Timing 0Full (color) frame timing adjustment with fin resolution58
  59. 59. AWVG7 Analog WideBand Video Generator Module 4 2 Identical HD Analog Test Signal 03 Channel with 30 MHz band width 0Supports major HD formats 1080/720p 4 High Quality Signal Generation 0 3 channel with 12 bits, 74.25 MHz clock 4 Frame Picture Feature (TG700 with Option FP) 0Can create PIC file from Windows BMP 4 Active Picture Scroll Pr/R Pb/B Y/G 0For both test signals and frame picture 4 Overlay Support 0Logo, ID text and circle overlay 4 Output Timing 0Full (color) frame timing adjustment with fine resolution59
  60. 60. 1. 75% Color Bar (With 100% White) ¡@ Full Amplitude 140 IRE ¡@ Hue and Saturation of Chrominance ¡@ Level of Luminance (Video Filter) ¡@ Amplitude, Timing, SCH Phase60
  61. 61. 2. FCC, NTC-7 Composite  Combine four kind of signal to one  Amplitude, Timing, SCH Phase, C to Y Gain &Delay, Short & Line time distortion, K Factor Rating, DGDP61
  62. 62. 3. Multiburst Test Signal ¡@ Six frequency from 0.5MHz to 4.1 or 4.2MHz ¡@  Frequency Response 0.5 1.25 2.0 3.0 3.58 4.1 MHz 4 8 10 14 16 18 Cycles62
  63. 63. Television Signal Formats Analog Composite Parallel Digital Composite Video PAL=17.7MHz (PAL/NTSC) NTSC=14.3MHz M R a B-Y t Serial Digital Composite G R-Y Composite A to D 143Mb/sec (NTSC) r Conv 10 Bits Parallel Serializer B Y Encoder 177Mb/sec (PAL) i x Color Difference Component 4Fsc Clock X10 Analog Video (PAL=17.7MHz) (Y, B-Y, R-Y) (NTSC=14.3MHz) DVD Component Digital Versatile Analog Video MPEG2 (Video) Disk (RGB) Protocol Program Stream B-Y R-Y Y 6.75MHz MPEG2 Sample 13.5MHz Protocol A to D A to D A to D Sample TransmissionRate for B-Y Audio Transport Stream Conv Conv Conv Rate for Y MPEG2 Channel and R-Y Data Program Tx Encoder Clock ITU-R BT.601-2 Picture SDH, ATM, Multiplexed 27MB/sec X10 MPEG2 Transmission Serial Digital Quality SONET or B-Y/Y/R-Y/Y/B-Y/Y Protocol Channel Analysis Component Analysis Modulated 10 Bits Parallel Analysis 270MB/sec RF Signals. Serializer ITU-R BT.601-2 Serial Digital Transmission Component 270MB/sec Channel ITU-R BT.601-2 Analog Composite MPEG2 Program MPEG2 Rx Parallel Digital Component Video (PAL/NTSC) 27MB/sec Decoder Protocol Data Transport Stream

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