Tag Archives: sigma delta
Impulse Invariant Transform
Introduction The impulse invariant transform (IIT) is a method of taking a continuous-time system H(s) and converting it to a discrete-time system. There are multiple ways of doing this, but the IIT does so with the constraint that the impulse response of the discrete-time system is a sampled version of the impulse response of the [...]
The Viterbi Sigma-Delta (at CircuitSage)
I’ve posted a guest article at Circuit Sage, detailing the derivation of a “Viterbi” over-sampling data converter. I’m quite proud of this one. Go over and check it out. FYI: this is also the reason I didn’t post directly to this site this week. I try to do a post per week, but the article [...]
Posted in Analog Professional Also tagged CircuitSage, data converter, Delta Sigma, oversampling, Viterbi Leave a comment
Unity STF | A sigma-delta linearization method
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 [...]
Posted in Analog Professional Also tagged continuous time, continuous time sigma-delta, linearity Leave a comment
Continuous time sigma-delta ADC noise shaping filter circuit architectures
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.
Posted in Analog Professional Also tagged active RC, ADC, continuous time, Gm-C, linearity, noise shaping filter 5 Comments
Example Simulink model & scripts for continuous-time sigma-delta ADC
I've put together a 2nd order continuous sigma-delta Simulink model as a starting point. This is the multi-port feedback configuration (feeds back into input of 1st and 2nd integrators).
Posted in Analog Professional Also tagged ADC, continuous time sigma-delta, example, feedback, matlab, quantizer, simulink 19 Comments
Response to edaboard question “How can I deal with 3rd HD in a 2nd SigmaDelta Modulator”
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 [...]
Dual DAC CTSD | Wider Bandwidth and Higher SNR — Part 2