Digital subchannel transceiver for transmitting data
US6693917B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1999 |
| Grant date | Feb 17, 2004 |
| Priority date | — |
| Expiry date | Aug 27, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/4908
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A system for transmitting subchannel data over the same media as high speed data, especially DC balanced high speed data. A digital transmitter receives subchannel data and modulates it onto a subchannel carrier as the host signal in the preferred embodiment using frequency shift keying. The FSK subchannel carrier is added by superposition to the high speed data signal. At the receiver, a low pass filter filters out the subchannel carrier frequency components which are then amplified and subjected to a two-pole anti-aliasing filter to remove the third and fifth harmonics. Analog-to-digital conversion is followed by a digital mix down to remove the subchannel carrier component using a local oscillator at the subchannel carrier frequency. An FIR low pass filter having a triangular time domain response performs anti-aliasing and leaves as an output only frequency components at the positive and negative deviation frequency for Mark and Space. Mark and space detectors then determine the relative magnitude of the signal received at the positive and negative deviation frequencies in the complex phasor domain to determine when Mark and Space frequencies are being received. Because of the a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.