Tag Archives: linearity

Unity STF | A sigma-delta linearization method

By Poojan Wagh | Published: November 23, 2008
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 [...]
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Continuous time sigma-delta ADC noise shaping filter circuit architectures

By Poojan Wagh | Published: November 18, 2008
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.
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Response to edaboard question “How can I deal with 3rd HD in a 2nd SigmaDelta Modulator”

By Poojan Wagh | Published: August 30, 2008
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 [...]
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Definition of IP3

By Poojan Wagh | Published: August 28, 2008
This point, where |A×x| = |c×X3| is the third-order intercept point.
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