Narrow-band filter including sigma-delta modulator implemented in a programmable logic device
US6600788B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1999 |
| Grant date | Jul 29, 2003 |
| Priority date | — |
| Expiry date | Sep 10, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H2017/0692
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A narrow-band bandpass filter is implemented in a field programmable gate array (FPGA). An analog-to-digital converter quantizes an input analog signal with a high degree of precision to produce input data samples. A sigma-delta modulator re-quantizes the samples with a substantially lower degree of precision. The re-quantized samples are passed through a bandpass, lowpass, or highpass, finite impulse response (FIR) filter which operates at the lower degree of precision. The reduced degree of precision enables a substantial reduction in the number of resources required to implement the narrow-band bandpass, lowpass, or highpass filter in the FPGA. The modulator includes a predictor filter which has a center frequency coinciding with that of the FIR filter, and redistributes noise such that it is lowest within the passband of the FIR filter. The narrow-band filter design can be adapted to incorporate a single or multi-rate decimator configuration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.