Enhanced delta modulation encoder
US4509037A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 1, 1982 |
| Grant date | Apr 2, 1985 |
| Priority date | — |
| Expiry date | Dec 1, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/02
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An improved analog-to-digital encoder comprising an enhanced delta modulation encoder. The enhanced delta modulation encoder includes a spectrum tilter, a 1 bit analog-to-digital converter, a sampling circuit and an internal decoder. An analog input signal and an internal analog signal from the internal decoder are summed to provide an analog dither which is essentially an internal error signal. The analog dither signal is tilted by the spectrum tilter and is provided to the 1 bit analog-to-digital converter which generates a digital signal. The sampling circuit receives the digital signal from the analog-to-digital converter and generates a digital output which is fed back to the internal decoder. The spectrum tilter comprises at least three integrator circuits and a clipping circuit connected in parallel to two of the three integrator circuits. The three integrator circuits tilt the frequency spectrum of noise above the maximum frequency of interest, and the clipping circuit prevents the encoder from becoming unstable. A digital filter may be connected to the output of the sampling circuit in order to filter the digital output to make it compatible with systems commonly employed …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.