MT92210 Zarlink Semiconductor, MT92210 Datasheet - Page 80

• Manufacturer Part Number: MT92210
• Description: 1023 Channel Voice Over ip (VoIP) Processor
• Manufacturer: Zarlink Semiconductor

MT92210
Data Sheet
indicate the beginning of a voice period; in the second, all silence packets are indicated with a marker bit = ‘1’, as
well as the first packet at the beginning of a voice period. Finally, instead of calculating its own CN energy and
generating the packet itself, the MT92210 can use a preprogrammed CN packet. This preprogrammed packet can
be of variable length, allowing spectral data to be passed along as well as an energy value. Preprogrammed
packets must be written into external SSRAM A by an agent through the CPU interface and may be updated
periodically. Because a pointer is given to the preprogrammed packet, its payload may be changed in a glitch-free,
atomic way. Spectral CN packets may be up to 64 bytes in length.
The silence suppression process also monitors and counts underruns that occur on the RX TDM side. The
underrun information from the RX side is passed along and is written to the TX circular buffer. The silence
suppression process can thus keep a 16-bit Underrun Count of the number of underrun events that have occurred.
The format of the TX Silence Suppression Structure varies according to whether or not the silence suppression
decision is being taken internally or if it is being fed from an outside agent, and according to whether or not the
generated CN packet will be a white energy value or a preprogrammed spectral value.
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