In a previous post, I discussed the trade-offs in linearity of several continuous-time sigma-delta schemes. In this post, I will describe a method that linearizes the sigma-delta noise-shaping filter (NSF). That is, the scheme presented in this article greatly suppresses the linearity requirements on the noise-shaping filter. This method applies to both discrete-time and continuous-time […]
The continuous-time sigma-delta (CTSD) analog-to-digital converter (ADC) is a class of sigma-delta analog-to-digital converters that utilize a continuous-time noise-shaping filter (NSF | H(s)). In this post, I analyze a few noise-shaping filter (NSF) architectures that affect highly linear CTSD ADC’s.
In response to: How can I deal with 3rd HD in a 2nd SigmaDelta Modulator It’s possible that the OTA is limiting you. Doing a matlab model of the sigma-delta and running it should tell you whether it is a circuit problem or a system-level problem. My hunch is that it’s a system-level problem: the […]