Receiver with filters offset correction
US5757864A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 1995 |
| Grant date | May 26, 1998 |
| Priority date | — |
| Expiry date | Aug 17, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention relates to circuitry for a receiver having a low cost filter using automatic alignment of the center frequency of signals input to the filter to suppress noise and out-of-band signals from the filter output over a narrow bandwidth. An RF input signal to the receiver is downconverted to an IF frequency using a VCO, and the IF signal is provided to the low cost filter. The output of the filter is input to a frequency correction circuit and a distortion detection circuit. The distortion detection circuit provides an error signal including positive frequency shift errors determined from digital ones identified from the filter output signal, and negative frequency shift error signals determined from digital zeros in the filter output signal. The distortion detection circuit output is then provided through an infinite impulse response filter which integrates the distortion detection output to provide a voltage control signal to a voltage control input of the VCO and the frequency correction circuit. The VCO then automatically centers the frequency of the signal input to the low cost filter to suppress noise and out-of-band signals, and the frequency correction circu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.