Method and apparatus for eliminating deadband in digital recursive filters
US4195350A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 19, 1978 |
| Grant date | Mar 25, 1980 |
| Priority date | — |
| Expiry date | Jun 19, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/0461
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Method and apparatus for eliminating deadband effects in digital recursive filters caused by rounding of the quantization of products within the filter, wherein the product is represented by a digital word, consists of truncating the absolute value of the product-representing word to the next lower digit by dropping a number of least significant digits determined by the value of the multiplier and if any of the dropped digits is a "one", adding a least significant "one" to the truncated number while retaining the sign of the pre-truncated word, and repeating the process at the cycling frequency of the filter, until a steady state is reached at which the difference between the input and output of the filter becomes zero. The concept is described as embodied in a digital system utilizing a recursive filter for reducing noise in a color television signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.