Apparatus and method for a combination D/A converter and FIR filter employing active current division from a single current source
US5995030A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 12, 1995 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | Sep 12, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/504
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An active current steering semi-digital FIR filter for a digital-to-analog conversion circuit, which includes a shift register having a 1-bit digital input stream and a plurality of output taps, where each output tap provides a 1-bit signal which has a value of a logic 1 or a logic 0, and a plurality of current paths, where each path includes an active element, such as a transistor, having a relatively high output impedance, which is connected to a common current source, and to an op amp for current-to-voltage conversion. The relatively high output impedance of the active current steering element causes any error term resulting from offset at the op amp inputs to be minimized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.