Robbed bit signaling identification in a PCM modem
US6272171A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 1999 |
| Grant date | Aug 7, 2001 |
| Priority date | — |
| Expiry date | Jan 28, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J3/125
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Methods are provided for determining whether any slots of a modem frame are subject to robbed bit signaling (RBS), and whether the robbed bit signaling is .beta.-codec robbed bit signaling. From an obtained DIL sequence, an ordered table of level values for each slot is generated. In determining whether any slots are RBS slots, distances between adjacent levels of the table for each slot are obtained and are compared to a "zero distance" threshold value in order to determine the number of distances which exceed the "zero distance" value. For each slot, the number of zero distances are compared to a threshold value, and if the number of zero distances exceeds the threshold value, the slot is declared to be a RBS slot. Zero distance thresholds for each slot are generated by finding a function of a maximum distance for that slot among the adjacent levels. In determining whether any RBS slots are .beta.-codec slots, distances are found between corresponding levels of the ordered tables. If substantially more than half of the distances from one slot to the others are found to be greater than a zero distance threshold value, the slot is determined to be a .beta.-codec slot.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.