Adaptive digital quantization noise cancellation filters for mash ADCs

US9768793B2 · kind B2 · utility

Assignee

• Analog Devices Global Unlimited Company · BM

Inventors

• Qingdong Meng · Tangshan City, CN
• Hajime Shibata · Toronto, CA
• Richard E. Schreier · Toronto, CA
• Martin S. McCormick · El Segundo, US
• Yunzhi Dong · Weehawken, US
• Jose Barreiro Silva · Burlington, US
• Jialin Zhao · 红钢城街道, CN
• Donald W. Paterson · Winchester, US
• Wenhua Yang · North Andover, US

Key dates

• Filing date: Nov 30, 2016
• Grant date: Sep 19, 2017
• Expiry date: Nov 30, 2036

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03M3/414
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

For continuous-time multi-stage noise shaping analog-to-digital converters (CT MASH ADCs), quantization noise cancellation often requires accurate estimation of transfer functions, e.g., a noise transfer function of the front end modulator and a signal transfer function of the back end modulator. To provide quantization noise cancellation, digital quantization noise cancellation filters adaptively tracks transfer function variations due to integrator gain errors, flash-to-DAC timing errors, as well as the inter-stage gain and timing errors. Tracking the transfer functions is performed through the direct cross-correlation between the injected maximum length linear feedback shift registers (LFSR) sequence and modulator outputs and then corrects these non-ideal effects by accurately modeling the transfer functions with programmable finite impulse response (PFIR) filters.