Complex bandpass digital filter
US4953184A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 1, 1989 |
| Grant date | Aug 28, 1990 |
| Priority date | — |
| Expiry date | Jun 1, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/0264
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An improved complex bandpass digital filter is disclosed. According to the invention, a complex bandpass digital filter having symmetric complex coefficients is implemented using a ROM look-up table. In operation, an input bit stream is latched at a desired decimation rate and the resulting latched bits are then used to address a ROM according to the following two-cycle process: First, the bits are applied in nomal order to the ROM to obtain the real (in phase) portion of the filter output. Second, the bits are bit-reversed and then applied to the same ROM to obtain the imaginary (quadrature) portion of the filter output. Thus, complex outputs are obtained as a time-multiplexed stream from one ROM, resulting in reduced ROM storage capacity requirements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.