The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 28, 1993
Filed:
Apr. 17, 1992
Charles D Thompson, Austin, TX (US);
Crystal Semiconductor Corporation, Austin, TX (US);
Abstract
An analog-to-digital converter includes a two-bit delta-sigma modulator. The delta-sigma modulator is comprised of a first stage integrator (10) that feeds a noise shaping circuit (18). The output of the noise shaping circuit (18) is input to a two-threshold imbedded ADC (20) to provide the two-bit output. This output of the imbedded ADC (20) is input to a digital filter (22) to provide the filtered digital output, this filtering high-frequency noise. The output of the imbedded ADC (20) is also fed back through a three-level DAC (24) to a summing junction on the input of the integrator (10). The three-level DAC 24 has three states that are output with one state being a 'do nothing' state. The thermal noise performance of the delta-sigma modulator as a function of the quantizer threshold voltages is first simulated and then the value of the quantizer thresholds selected to provide optimum signal-to-thermal noise performance.