Equalization arrangement
US4800573A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Nov 19, 1987 |
| Grant date | Jan 24, 1989 |
| Priority date | — |
| Expiry date | Nov 19, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03044
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A voiceband data signal comprised of frequency-division-multiplexed primary and secondary channels is applied to the receiver portion of a modem. Circuitry within the modem for recovering the primary channel data includes an anti-aliasing filter, A/D converter, Hilbert filter, demodulator, fractionally-spaced equalizer, carrier recovery circuit and decision circuit. An error signal put out by the decision circuit is used by the equalizer to update its coefficients, and thus its transfer function. Rather than using a bandpass filter to remove the secondary channel energy prior to sampling and equalization, the receiver relies on the fractionally-spaced equalizer to suppress the secondary channel energy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.