OFDM timing and frequency recovery system
US5889759A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 13, 1996 |
| Grant date | Mar 30, 1999 |
| Priority date | — |
| Expiry date | Aug 13, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2679
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A synchronizing apparatus for a differential OFDM receiver that simultaneously adjust the radio frequency and sample clock frequency using a voltage controlled crystal oscillator to generate a common reference frequency. Timing errors are found by constellation rotation. Subcarrier signals are weighted by using complex multiplication to find the phase differentials and then the timing errors. The reference oscillator is adjusted using the timing errors. Slow frequency drift may be compensated using an integral of the timing error. Frequency offset is found using the time required for the timing offset to drift from one value to another.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.