Multi-dweller access moves up the curve

Equipment makers are starting to look at ways of providing digital TV to people who live in blocks of apartments.

UK-based set top box maker Pace Microtechnology is moving into providing telecom equipment with a new system to allow satellite and cable TV operators to offer their services to large blocks, while X-Digital Systems in the US is using 48 of ADI's Blackfin processors in a satellite receiver with FM modulator that allows satellite operators to stream digital audio to hotels and apartment complexes.

Many blocks of flat have restrictions on satellite dishes and cable access, and Pace has developed technology that essentially puts a small video headend on the roof of the building. This MultiDewellerUnit (MDU) is connected to the individual flats by the existing coax cable network used to pipe terrestrial TV to flats, so no new wires are needed, and would connect to a new set top box in the home. It uses QAM modulation to transmit the TV over the coax with an agile frequency hopping protocol to avoid interference, with an uplink from the set top box to the headend so that the user can change channels.

This technology would allow HDTV services and broadband data access up to 30Mbit/s with the same performance as today’s satellite or cable TV set top box in the living room. Linking a hard disk drive into the headend could also provide a local video on demand service.

The potential problem is that the equipment has to sit on the roof of the building and work reliably 24/7 for many years, and Pace has to demonstrate that it can meet the quality standards of other network equipment makers.

So Pace is now working with cable TV suppliers to put coax networks that are up to 30 years old into the lab to prove that the system will work and to demonstrate that it scales up to blocks with up to 50 flats. This covers over 60% of 'multi dwelling units' in Europe, says Pace.

US satellite set top box maker X-Digital is also using the coax infrastructure. Its MSL384 satellite receiver converts digital satellite signals to FM analogue signals that can be picked up by standard consumer audio receivers. Each receiver employs 48 Blackfin processors to decode 384 MPEG 1 Layer 2 Audio streams. Each processor handles eight MPEG 1 Layer 2 Audio streams, as well as ADI's AD9726 TxDAC 16-bit,
400 MSPS transmit digital-to-analogue converter onto the COAX network .

"With the MLS384, X-Digital is taking aim at the MDU audio services market. Because each Blackfin enables us to process multiple digital audio signals, X-Digital is able to leverage the MLS384 for the high density and low power needed in the MDU market," said Ian Lerner, President of X-Digital Systems. "In the past, carriers have lost out on this market because of their inability to provide satellite dish installs to every apartment."