Signal processing system with baseband noise modulation and noise fold back reduction
US6842486B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 2003 |
| Grant date | Jan 11, 2005 |
| Priority date | — |
| Expiry date | Jun 19, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/50
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digital-to-analog converter (“DAC”) system utilizes chopping modulation technology to remove 1/f and other baseband noise from a baseband of a signal of interest. Chopping modulation and demodulation circuitry of the DAC operate at a chopping frequency equal to approximately one-half of a digital input signal sampling frequency. Chopping at one-half the sampling frequency allows fold back into the baseband of the input signal's frequency components and reduces fold back of noise, such as quantization noise, residing outside the baseband. In a further embodiment, a notch filter attenuates signals having frequencies around the chopping frequency prior to chopping to reduce fold back of noise into the baseband due to parasitic modulation. Coordination of chopping timing also reduces noises in the output of the DAC system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.