Nevion SDI-CHO-2x1-PB - Manual (Page 4)

SDI-CHO-2x1/ SDI-CHO-2x1-PB Rev. E
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1 Product overview
The
flashlink
SDI-CHO-2x1-PB/SDI-CHO-2x1 is a serial digital video 2x1 change-over
module providing high performance line protection for various signal formats from
1Mbps up to 540Mbps. The unit can be configured to perform cable equalizing and re-
clocking of SMPTE 259M and DVB-ASI signal formats. The switching criteria can be
selected to be based on loss of input signal or loss of lock (re-clocker). The switch can
either be latching or non-latching (in loss of lock mode, only latching switch is
available). It is also possible to control the switch with GPI inputs, with the GYDA
system controller or with the open protocol RS422 interface.
The two inputs typically provide automatic cable equalizers for up to 300 meters of
cable (Belden 8281A at 270Mbps) with a 2 x 1 switch in front of a re-clocker with 4
outputs. The re-clocker supports the bit-rates; 143, 177, 270, 360 and 540Mbps. For
other rates, the re-clocker automatically switches to bypass mode and the SDI-CHO-
2x1 will work as a non-re-clocking 2x1 change-over unit with cable equalizer. The SDI-
CHO-2x1 also has a special DVB-ASI mode, enabling all possible rates including
empty transport streams with only K28.5 padding packets. 2 outputs are non-inverting
to support DVB-ASI compatibility.
The SDI-CHO-2x1 is designed for various line protection applications for studio,
campus, broadcast and telecom. The SDI-CHO-2x1-PB also features a relayed bypass
of both inputs to its respective outputs ensuring signal bypass at power down or card
failure/ upgrade.
New in firmware version 2.0.0 or newer: When latched to standby input, latch will not
hold against missing signal on standby input if the signal on main input has been
restored. Also, a secondary timer has been added, which handles de-bouncing of the
“signal on main input returns” condition. The primary timer handles de-bouncing of LOS
on both main and standby inputs.
1.1 Product versions
SDI-CHO-2x1 2x1 SD-SDI changeover
SDI-CHO-2x1-PB 2x1 SD-SDI change over with passive bypass
Figure 1 - SDI-CHO-2x1 Serial Digital Video Change-over