Direct conversion receivers and filters adapted for use therein
US6335656B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1999 |
| Grant date | Jan 1, 2002 |
| Priority date | — |
| Expiry date | Sep 30, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/30
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A direct conversion receiver having a homodyning section fed by a received radio frequency signal having a carrier frequency and reference signal having the carrier frequency; and a filter coupled to the monodyning section. The filter includes a plurality of serially coupled high pass filter stages. The high pass filter section acts as a DC offset correction loop that eliminates the serial effect of many amplifier sections on DC offsets arising within components, while maintaining a sufficiently low cutoff frequency to avoid adversely impacting information integrity at higher frequencies. The high pass filter sections also enable the integration of the needed capacitors, thus minimizing external components and connections. Each filter stage includes an amplifier and a low pass filter coupled in a negative feedback arrangement with the amplifier. Each low pass filter is adapted to have the cutoff frequency thereof switch from an initial high cutoff frequency to a subsequent lower cutoff frequency. A high filter stage of a direct conversion receiver is provided that includes in a low pass filter feedback section thereof a capacitor and a resistor section coupled to the capacitor. The…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.