Analog-to-digital and digital-to-analog conversion system and echo cancellation device including the same
US5001480A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1988 |
| Grant date | Mar 19, 1991 |
| Priority date | — |
| Expiry date | Oct 17, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/238
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A conversion system is disclosed for performing either an analog-to-digital A/D conversion associated with an amplification step or a digital-to-analog D/A conversion associated with an attenuation step. The system includes apparatus (115) for receiving a input digital word to be processed, i.e. converted into analog and then attenuated, and apparatus (165) for receiving a input analog value to be processed, i.e. amplified for scaling purposes and then converted into digital. It also includes a digital-to-analog D/A converter (110), an attenuator (120) for attenuating the analog output of D/A converter (110), and a comparator (150) for comparing the value of the input analog value to be processed and the output of said attenuator (120). The processing of the D/A-attenuation process is performed by both the D/A converter (110) and attenuator (120). In order to achieve the A/D-amplification process, the system further includes generator apparatus (140) for generating a sequence of digital words to the D/A converter (110), and storage apparatus (220) for storing among this sequence, the digital value that minimizes the difference between both input of comparator (150). This digital va…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.