GS3471 datasheet(37/179 Pages) SEMTECH

37 / 179 page

GS3471

Final Data Sheet Rev.4

PDS-060498

September 2017

37 of 179

Semtech

www.semtech.com

4.12 Timing Signal Extraction

The GS3471 extracts timing information from the input data stream and provides FVH

timing reference signals.

Video timing signals are only operational in SMPTE mode (SMPTE_BYPASS = HIGH).

It takes one video frame to obtain full synchronization of the received video standard.

Note: Both 8-bit and 10-bit TRS words are identified. Once synchronization is achieved,

the device continues to monitor the received TRS timing information to maintain

synchronization.

4.12.1 Automatic Switch Line Lock Handling

The principle of switch line lock handling is that the switching of synchronous video

sources will only disturb the horizontal timing and alignment, whereas the vertical

timing remains in synchronization – i.e. switching between video sources of the same

format. Switch line lock handling is only available in SMPTE mode.

To account for the horizontal disturbance caused by a synchronous switch, the flywheel

must be re-synchronized, immediately following a switch line, as defined in the SMPTE

recommended practice document RP168-2002.

The synchronous switch point is defined for all major video standards in SMPTE

RP168-2002. The device automatically re-synchronizes the word alignment block and

timing signal generator at the switch point, based on the detected video standard.

The switch line is defined as follows:

•

For 525 line interlaced systems:



resynchronization takes place at the end of lines 10 & 273

•

For 525 line progressive systems:



resynchronization takes place at the end of line 10

•

For 625 line interlaced systems:



resynchronization takes place at the end of lines 6 & 319

•

For 625 line progressive systems:



resynchronization takes place at the end of line 6

•

For 750 line progressive systems:



resynchronization takes place at the end of line 7

•

For 1125 line interlaced systems:



resynchronization takes place at the end of lines 7 & 569

•

For 1125 line progressive systems:



resynchronization takes place at the end of line 7

Note: Unless indicated by SMPTE ST 352 payload identifier packets, the GS3471 does

not distinguish between 1125-line progressive segmented-frame (PsF) video and

1125-line interlaced video operating at 25 or 30fps. However, PsF video operating at

24fps is detected by the device.

A full list of all major video standards and switching lines can be found in SMPTE

RP168-2002.

GS3471 数据表(PDF) 37 Page - Semtech Corporation

GS3471 数据表(HTML) 37 Page - Semtech Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载