ANSI CTA-2020 pdf free download

ANSI CTA-2020 pdf free download.Other VBI Waveforms.
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 Y2 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.
* Because this section covers signals received under all types of real world TV broadcast signal
conditions, this wider range should be anticipated.
5.5.5 Spurious Signals
Spurious signals, overshoot and undershoot on the bits shall not be more than ± 10 IRE units.
5.6 System Considerations
5.6.1 Synchronization of AMOL and Video
A set of bits associated with a given frame/field of video shall remain associated with that frame/field.
Delaying or advancing the AMOL data with respect to the active video information will cause erroneous
reporting to occur.
5.6.2 Shifted AMOL signals
Although lines 20 and 22 of fields one and two are authorized by the FCC for AMOL use, the data can appear in other scan lines due to unintentional shifting caused by tape machines, time base correctors, compression equipment, editing equipment, and the like. For example, although it is specified to expect AMOL on line 20 and/or line 22, it is possible to find these “signals” shifted up or down one or two lines (or more) and/or shifted to the opposite field location.
Receiving equipment that is designed to pass the AMOL signal, such as compression encoder/decoders, TBCs (time base correctors), etc. are not expected to compensate for shifted AMOL code. This forces the shifting problem to be solved rather than covered up.
6 TVG1x and TVG2x Waveforms
There are two waveforms defined in this section—TVG1x and TVG2x.
6.1 TVG1x Waveform
The signal characteristics of the TVGI x format shall be identical to the format specified in CEA-608-C
Section 5 with the differences described in this section.
6.1.1 Signal Characteristics for Encoding
The encoded data amplitude level of a logic 1 data bit shall vary from CEA-608-C Section 5 as indicated in Table 3.ANSI CTA-2020 pdf download.