GS1575B / GS9075B HD-LINX® II Multi-Rate SDI

Automatic Reclocker

Data Sheet

40063 - 1

June 2009

21 of 28

4.9 DVB-ASI Operation

The GS1575B/9075B will also re-clock DVB-ASI at 270 Mb/s. When reclocking DVB-ASI

data set the ASI/177 pin HIGH to prevent a false lock to 177Mb/s. If ASI/177 is not set

HIGH, a false lock may occur since there is a harmonic present in idle patterns (K28.5)

which is very close the 177 Mb/s data rate (EIC 1179). Note that setting the ASI/177 pin

HIGH will disable the 177 Mb/s search when the device is in Auto mode, consequently

the GS1575B/9075B will not lock to that data rate.

4.10 Lock and LOS Indicators

The LOCKED signal is an active high output which indicates when the PLL is locked.

The internal lock logic of the GS1575B/9075B includes a system which monitors the

Frequency Acquisition Loop and the Phase Acquisition Loop as well as a monitor to

detect harmonic lock.

The LOS (Loss of Signal) output is an active HIGH output which indicates the absence of

data transitions at the DDIx input. In order for this output to be asserted, transitions must

not be present for a period of typically 5.14 us. After this output has been asserted, LOS

will deassert typically 5.14 us after the appearance of a transition at the DDIx input. This

timing relationship is shown in Figure 4-4:

Figure 4-4: LOS signal timing

NOTE: LOS is sensitive to transitions appearing at the input, and does not distinguish

between transitions caused by input data, and transitions due to noise.

DATA

LOS

5.14 us

5.14 us