Network-technologies DVB-ASI to IP Manual de usuario descargar pdf (Pagina 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:

1 2 ... 53 54 55 56 57 58 59 60 61 62 63 ... 92 93

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Network-technologies DVB-ASI to IP Manual de usuario Pagina 58