Network Technologies DVB-ASI to IP - Manual (Page 58)

ASI-IP-GTW User's Manual
Page 58
4 Options
This chapter describes functionality and operating instructions for
various additional product options.
4.1 1PPS/10MHz interface modules
In order to achieve exact bitrate control for use in SFN networks, the
ASI-IP-GTW may be equipped with 1PPS/10MHz interface modules.
The purpose is to lock the internal system clock of the ASI-IP-GTW to
external 1PPS/10MHz signals to obtain exact bitrate control. The
typical application is to receive a stream over IP network and send it
out on ASI connectors at a fixed, accurate rate. The transmitter needs
to transmit at the same rate.
Two options exist to lock the product to external time reference: A
separate 10MHz/1PPS module which occupies an ASI slot, or a
separate 1PPS input module that allows 8 ASI ports.
4.1.1 Separate 10MHz/1PPS module
Figure 29 shows a picture of the back panel when this module is
mounted.
Figure 29. ASI-IP-GTW with 1PPS/10MHz interface module equipped
The signals are:
o
10MHz. 50 ohm terminated input for a sinusoidal 10MHz signal.
o
1PPS. 50 ohm TTL input for a 1 pulse-per-second signal.
For physical parameters of these ports, see appendix B.
Both signals may be connected. However, the ASI-IP-GTW only uses
one of them at a time. The active input is selected from the “GPS” tab in
the ASI-IP-GTW WEB user interface.
4.1.2 1PPS interface
When 8 ASI outputs are required together with SFN operation, an
alternative to the 1PPS/10MHz module is to use a separate 1PPS
interface as described in the following figure.
Figure 30. ASI-IP-GTW with separate 1PPS interface module
The signals are: