System Description
Phasecom's SpeedDemon modem provides connectivity over a hybrid fiber/coax broadband cable network for any personal computer that supports an Ethernet 10BaseT interface. The cable modem is an external device which connects to a personal computer through an Ethernet adapter. SpeedDemon is an asymmetric modem making it ideal for applications such as the Internet. The modem is a frequency agile device employing Quadrature Amplitude Modulation (QAM) for for the downstream and Quaternary Phase Shift Keying (QPSK) for the upstream. The modem achieves speeds of up to 30 Mbps in the downstream direction and 2.56 Mbps in the upstream direction.
The SpeedDemon Network architecture consists of the SpeedDemon 2001, a headend network controller, a router, and the SpeedDemon cable modems.
The SpeedDemon 2001 headend network controller consists of an RF module, a modulator/demodulator, and a channel controller module. The headend controller, in its minimal configuration, can support up to 1000 SpeedDemon modems on the network. The system is scalable, allowing additional modules to be easily added at the headend rack to enable more users to join the network. The SpeedDemon 2001 interfaces with generic routers to provide connectivity from the desktop to local servers, Wide Area Networks (WANs) and the Internet.
Features
Specifications
| Modulation Scheme: Downstream Upstream | 64 QAM QPSK |
| Data Rate: Downstream Upsteam |
30 Mbps 2.56 Mbps |
| Operation Mode | Full Duplex |
| Operating Range: Downstream Upstream | 50 - 860 MHz 5 - 42 MHz |
| Channel Spacing: Downstream Upstream | 6 MHz 2 MHz |
| Frequency Stability | ±5 KHz |
| BER Performance: Downstream Upstream | 10-12 at 30 db C/N 10-6 at 20 db C/N |
| LAN Interface | IEEE 802.3/Ethernet RJ45 |
| RF Interface | Female "F" type |
| Local Control Interface | RS232 |