ANSI CTA-2020:2007 pdf free download – Other VBI Waveforms ANSI/CTA-2020 R-2014 (Formerly ANSI/CEA-2020 R-2014)
1 Scope
This standard, CEA-2020, specifies four Vertical Blanking Interval (VBI) waveforms in commercial use.
The electrical properties of the waveforms are covered, but the meaning of the payload data is not.
The waveforms apply to 525-line, interlaced (i.e. 480i) analog television signals.
The waveforms may be present on analog inputs and analog outputs, but no conformance requirements about the actual presence of the waveforms are defined in CEA-2020.
2 References
2.1 Normative References
The following standards contain provisions that, through reference in this text, constitute normative provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed in Section 2.1.1.
2.1.1 Normative Reference List
CEA-608-C, Line 21 Data Services, August 2005
SMPTE 170M, SMPTE Standard for Television—Composite Analog Video Signal—NTSC for Studio Applications, 2004
4 Waveform Summary
CEA-2020 is intended to aid in the identification, encoding and decoding of VBI waveforms used for the transport of AMOL, TVG1x and TVG2x payloads. Creation, modification or end-use of the payload data itself is not covered here.
These waveforms may be encoded for broadcast on lines 10 through 25. Line 10 is often used as a clamp line by analog equipment and placing data on it may render that equipment inoperable. Line 19 is primarily used for ghost cancelling, and is reserved for this purpose in terrestrial broadcasting. Line 21 is primarily used for data structures defined in CEA-608-C, and is reserved for this purpose in terrestrial broadcasting.
Lines 22 through 25 are part of the active picture area, and their use for data transport in broadcast television require the permission of the FCC.
The common industry terms, “AMOL”, “AMOL I”, and “AMOL II” refer to combinations of payloads and waveforms and do not directly map to the waveforms defined here as AMOL-48 and AMOL-96.The line numbering system used refers to the video as 262 ½ lines per field starting with line 1, 2 fields per frame (interlaced), 29.97 frames per second.
Levels are indicated in Institute of Radio Engineers (IRE) standard units, as defined in SMPTE 170M Annex B.
5 Automated Measurement of Lineups (AMOL) Waveforms
5.1 AMOL Signal Overview
5.1.1 Signal Locations
AMOL shall be encoded with either 48 bits per field or 96 bits per field, corresponding to 1 Mbps or 2 Mbps respectively. It is typically encoded on lines 20 and/or 22 and in one or both fields, however, it may appear on any VBI line, and both 48- and 96-bit forms may be mixed in the same signal. See Table 1.