GS2971 datasheet(30/148 Pages) SEMTECH

30 / 148 page

GS2971 3Gb/s, HD, SD SDI Receiver

Data Sheet

45898 - 2

September 2012

30 of 148

with downstream devices. The associated Parallel Clock input signal operates at 148.5

or 148.5/1.001MHz (for all 3Gb/s HD 10-bit multiplexed modes), 74.25 or

74.25/1.001MHz (for HD 20-bit mode), 27MHz (for SD 10-bit mode) and 13.5MHz (for SD

20-bit mode).

NOTE: For 3Gb/s 10-bit mode the device operates in Dual Data Rate (DDR) mode, where

the data is sampled at both the rising and falling edges of the clock. This reduces the I/O

speed requirements of the downstream devices.

Up to eight channels, in two groups, of serial digital audio may be extracted from the

video data stream, in accordance with SMPTE 272M and SMPTE 299M. The output signal

formats supported by the device include AES/EBU and three other industry standard

serial digital formats. 16, 20 and 24-bit audio formats are supported at 48kHz

synchronous for SD modes and 48kHz synchronous or asynchronous in HD/3G mode.

Additional audio processing features include group selection, channel swapping, ECC

error detection and correction (HD mode only), and audio channel status extraction.

Audio clock and control signals provided by the device include Word Clock (fs), Serial

Clock (64fs), and Audio Master Clock at user-selectable rates of 128fs, 256fs or 512fs.

4.2 SMPTE 425M Mapping - 3G Level A and Level B Formats

4.2.1 Level A Mapping

Direct image format mapping - the mapping structure used to define 1080p/50/59.94/60

4:2:2 YCbCr 10 bit data, as supported by the GS2971. See Figure 4-1:

Figure 4-1: Level A Mapping

4.2.2 Level B Mapping

The 2 x 292 HD SDI interface - this can be two distinct links running at 1.5Gb/s or one

3Gb/s link formatted according to SMPTE 292 on two 10-bit links (Y/C interleaved). For

1080p/50/59.94/60 4:2:2 video formats, each link should be line-interleaved as per

SMPTE 372M. See Figure 4-2:

Data Stream 1

Data Stream 2

EAV

HANC

SAV

Active Video

GS2971 Datasheet(PDF) 30 Page - Semtech Corporation