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The MMM-4711 and
MMX-4711 are part of a family of data transcoders for converting between the
commonly used MPEG2 Transport Stream formats for video distribution in the
broadcast industry.
With the MMM-4711 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 anything 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.
Provided the total sum of the ASI inputs does not exceed 0.9* x the set output rate, units can be cascaded to increase the number of ASI inputs into a single ASI output. |
The MMX-4711
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 has been cascaded then the MMX‑4711’s
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 are designed to fit IRT’s standard Eurocard frames and may be used
alongside any other of IRT’s analogue or digital Eurocards.
* 0.95 x with 188 bytes,
0.88 x with 204 bytes.
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