Motorola Return Path Demodulator

The Motorola RPD2000 is an essential component of a local access network configuration. It provides
the upstream link that is needed for communications with set-top terminals. The terminals provide
essential information such as Aloha interactive data, pay-per-view (PPV) purchases as well as critical
status monitoring data. Data is received by burst demodulator modules within the RPD2000. The
unit can be equipped with up to six modules, allowing data streams to be received from one to six
upstream QPSK modulated RF carriers. Each RF carrier can be tuned to a separate frequency, as
would be common in an interactive environment, or the same frequency, as would be more common in a
polling only environment. The RPD2000 demodulates, provides forward error correction, and
multiplexes this data into a single data packet that is transferred to the controlling processor via an
Ethernet port.
Control and configuration of the RPD2000 is accomplished via the headend configuration tool or
from the front panel control. RPDs are linked via an Ethernet connection in a local headend LAN.
Each demodulator board can be dynamically tuned. For added reliability, demodulators can be daisy
chained to allow for back-up capabilities.