Smoothing filter
US5018171A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 9, 1989 |
| Grant date | May 21, 1991 |
| Priority date | — |
| Expiry date | Aug 9, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L12/433
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Preamble smoothing for information character transmissions in a data transmission network is accomplished as follows. First, the smoothing filter identifies the start of a new preamble. If the start of a new preamble is identified and a previously received preamble has been extended, then the preamble is contacted by deleting an IDLE byte or, if the frame received prior to the initial IDLE byte was a frame fragment, then the information character preceding the initial IDLE byte is deleted. Following the contraction of the preamble, a determination is made as to whether next received byte is an IDLE byte. If it is not, then the preamble is extended by inserting an IDLE byte and the smoothing filter begins searching for the start of a new preamble. If it is, then a counter is incremented. If the counter has not yet reached its preset threshold, then the next byte is checked to determine whether it is an IDLE byte. If it is, then the counter is again incremented. This iterative process continues until the counter threshold is reached. At that point, the smoothing filter again begins searching for the start of a new preamble.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.