1	Timing and Synchronization in a Multi- Standard Multi- Format Video Facility Bill Cohn Application Engineer IPTV DTV Symposium November, 2002
2	SMPTE RP 168 Definition of Vertical Interval Switching Points for Synchronous Video Switching Uncompressed Composite or Component for Analog and Digital Payloads After Sync but Early in the VBI protects Time Code and Audio Guidance on using SD Analog Sync on Digital Formats Tri-level Sync Covers all Frame Rates
3	Analog Synchronization
4	Analog Timing Synchronizing the three basic parameters to match a reference Vertical Sync = Field Timing Horizontal Sync = Line Timing Color Sync = Subcarrier Timing
5	GenLock Reference - Black Burst Black Burst is used for system timing The sync is used for Genlock and drive signals The color burst is used for color (SCH) reference The relationship of burst to sync is used for GenLock, SCH Phase, and color frame reference
6	Horizontal Sync Extraction Simple differentiating circuit Sharp negative pulse for drive circuits Ignore positive pulse
7	NTSC Horizontal Blanking
8	Vertical Sync Extraction Simple integrating circuit Use negative pulse for vertical drive circuits Lines 4,5,6 and 266.5, 267, 268.5 Line pulses present to prevent H drift
9	525 Vertical Blanking- Four Field Color
10	Timing Delay within a Facility Delay is a function of type of cable and the length of cable Video processors add delay
11	Basic Timing System
12	How to Measure Analog Timing Using Waveform Monitor and Vectorscope Select External Reference Make measurements at 50% point Compare A and B Input Start by measuring vertical timing of signals Next step measure horizontal timing of signals Perform burst phasing of signals using vectorscope
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14	Dual Master SPG System
15	HD Analog Horizontal Timing HD Tri-Level Sync Signal Fast rise times provide accurate timing edges Tri-level period much shorter than analog BB Improved jitter performance
16	HD Analog Vertical Timing
17	Digital Timing Some digital switchers can Auto Time Processing delays impact vertical timing Analog Black Burst or SD/HD Black HD Tri-Level Sync Signal Fast rise times provide accurate timing edges Tri-level period much shorter than analog BB Improved jitter performance External Reference properly terminated Horz and Vert Timing Component Video- No Color Framing
18	SMPTE 292 Digital Horizontal Line
19	Component Horizontal Line
20	Digital Horizontal Timing No sync with in digital signal EAV End of Active Video 3FF,000,000,XYZ SAV Start of Active Video 3FF,000,000,XYZ XYZ Word Bit 8 P or I Bit 7 VBI or Active Bit 6 EAV or SAV Bits 5-2 Error Correction HD adds Line and Field Number
21	SMPTE 318M 10 Field Sequential Identification Signal Inserted in 525/59.94 systems at lines 15 & 278 Start pulse is always present Frame Count pulses 2 to 5 Sixth pulse present on 278 ONLY At 29.97 Hz it takes 5 Frames to Lock Digital Audio Audio Buffered
22	SMPTE 318M Black Burst with 10 Field ID
23	Digital Vertical Timing No field pulse is present Y = 040 Cb= 200 Y = 040 Cr= 200
24	How to Measure Digital Timing Use Digital Waveform monitor Select correct external reference- terminated Set Pass EAV and SAV values Start with vertical timing using reference point of first line of active video. Measure horizontal timing using SAV pulse Amplitude should be the same to ensure correct field
25	Audio Timing Video Lock: It’s Synchronous but not Framed
26	Reframing at Front End
27	Embedded Audio
28	Mutes DIGITAL AUDIO MUTE does not equal ANALOG MUTE Digital Audio Mute is a particular digital word Analog Mute when converted to digital can contain noise dc level
29	Summary SMPTE RP 168 Definition of Vertical Interval Switching Points for Synchronous Video Switching Analog or Digital Sync as Reference Tri-level Sync Covers all Frame Rates Component Video requires Line and Field Timing EAV and SAV SMPTE 318 Defines 10 Field Sequence Audio Timing may require buffering
30	THANK YOU! Useful Application Notes www.tektronix.com/video Bill Cohn Application Engineer William.e.cohn@tektronix.com 847-524-1899