The MMM-4711 and MMX-4711 are a part of a family of data transcoders and are available from IRT Electronics for converting between MPEG2 transport stream formats for video distribution in the broadcast industry.
With the MMM-4711 data transcoder, up to four ASI signals can be combined together and converted into a single ASI signal with a settable output payload rate.
The sum of the ASI input payload rates can be up to approximately 0.9* x the set ASI output payload rate.
Inputs may be 188 or 204 byte packet lengths, burst or continuous and may have energy dispersal scrambling, interleaving and/or Reed Solomon bytes included.
An individual input may be up to 0.9* x the full set ASI output payload rate, if the other inputs are unused. The output ASI stream is a valid stream, which complies with all facets of ETR290.
Units can be cascaded to increase the number of ASI inputs into a single ASI output if the total sum of the ASI inputs does not exceed approximately 0.9* x the set output rate.
The MMX-4711 data transcoder separates the combined ASI signal back into the original four ASI signals (at their original rates and without any modification of the stream, or stream timing).
If more than one MMM‑4711 data transcoder is cascaded, then the MMX‑4711 data transcoder cascade in the reverse order. Inputs are automatically equalised for lengths of up to 250m of Belden 8281 or equivalent cable.
Front panel indication and relay alarm on the MMM‑4711 transmitter shows if there is an input data rate violation. Corresponding alarm on the MMX‑4711 receiver shows a loss of ASI input.
The MMM-4711 and MMX-4711 data transcoders are designed to fit IRT’s standard Eurocard frames and may be used alongside any other of IRT Electronics’ analogue or digital Eurocards.
MMM-4711 and MMX-4711 data transcoders have the following features:
- Up to four ASI streams on one ASI link
- Units may be cascaded to increase the number of ASI inputs
- Recovers transmitted ASI signal without any added PCR jitter and with minimal user setup
- Maintains original ASI rate, packet size and coding (energy dispersal scrambling, interleaving or Reed Solomon bytes)
- Suitable for Single Frequency Networks (SFN)