Timing recovery in a multi-tone modem
US6546056B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 28, 1999 |
| Grant date | Apr 8, 2003 |
| Priority date | — |
| Expiry date | May 28, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2675
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A timing recovery apparatus for use in a receiver in a multicarrier transmission system is provided. The apparatus includes a receive signal buffer, a pointer register containing an address to a location within the receive signal buffer, a time to frequency domain signal converter, a digital filter, and a control circuit. The signal converter accepts data from the receive signal buffer. The samples that are fed into the converter are determined by an address stored in the pointer register. The digital filter is connected to the converter, and is essentially a bank of single-tap filters. One of the converter outputs corresponds to a pilot tone, and thus the digital filter provides a filtered pilot tone. The phase of the pilot is also examined, preferably by examining the filter tap corresponding to the pilot. The control circuit accepts the pilot phase signal and responsively updates the pointer register. Alternatively, the control circuit updates the pointer register by deriving a phase signal directly from the relevant converter bin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.