Integrated upstream amplifier for cable modems and cable set-top boxes
US8013768B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 2002 |
| Grant date | Sep 6, 2011 |
| Priority date | — |
| Expiry date | Apr 8, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G1/0088
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An upstream amplifier is integrated on a substrate with a digital-to-analog converter (DAC) to form an integrated circuit. In an embodiment, a low-pass filter is also integrated on the substrate. The output signal level of the upstream amplifier is controllable. In embodiments, fine adjustments are made to the output signal level of the upstream amplifier by varying a bias current of the DAC. A software control bit is used to switch between a power-on mode of operation and a power-down mode of operation. The upstream amplifier transmits in a burst mode. The power consumption of the upstream amplifier scales with the amplifier's output signal level. A high degree of matching is attained between the positive and negative paths of the upstream amplifier. This provides high immunity from common-mode disturbances such as substrate noise, clock spurs, and glitches caused by a gain change.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.