Digital processing radio receiver with adaptive bandwidth control
US6178211A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 1999 |
| Grant date | Jan 23, 2001 |
| Priority date | — |
| Expiry date | Oct 22, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2001/1054
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A carrier-based signal is received from a tuner and is digitized to produce a digital intermediate frequency (IF) signal. Automatic gain control is applied to the carrier-based signal either prior to or after digitization. An adaptive intermediate frequency bandwidth control system detects IF signal level after channel filtering. The level is compared to a predetermined threshold having a value related to the known signal level of the AGC'ed signal which is being input to the channel filter in order to provide a measure of either 1) the presence of interfering adjacent channels, or 2) reception or a weak signal which can't be compensated for by AGC. The IF bandwidth is narrowed in either circumstance. Digital FIR or IIR filtering is used. The invention allows bandwidth switching to be done very quickly with minimal transient effects. A threshold value is selected depending upon the IF channel bandwidth being used at any given time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.