Digital signal receiver with FM interference elimination capability
US4380082A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 24, 1981 |
| Grant date | Apr 12, 1983 |
| Priority date | — |
| Expiry date | Apr 24, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/08
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The invention eliminates an FM interference from a digital signal when the interference occurs because the FM and digital signals are transmitted over adjacent routes and sharing a common frequency band. An error detector finds a difference between a detected baseband digital signal and an assumed transmission code, which is taken from the baseband signal. The detector produces a first error signal responsive thereto. A phase synchronizing circuit produces an output signal synchronized with the first error signal. A coefficient circuit multiplies the output of the synchronizing circuit by a complex coefficient which is then subtracted from the baseband signal. A second error detector produces a second error signal responsive to the difference between the output of the subtractor and a discriminated transmission code. Responsive thereto to a control circuit varies the complex coefficient to produce an output which is the original baseband signal, free of the FM interference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.