Embedded Data Converters

We recommend you to submit your preliminary or firm registration at least 4 weeks before course start to ensure a seat on the course.

New date to be decided

TECHNOLOGY FOCUS 
Powerful digital signal processing has been the key enabler of many technological breakthroughs during the last decades. So-called 'digital' communications brought us a worldwide wireless communications network and high-speed wireline internet access. Processor based mechatronical systems have increased efficiency, reduced waste, and raised security in nearly every application you may think of.
The interface between the "analogue" environment and the digital signal processing is the data converter. Steadily increasing resolution and bandwidth of the A-to-D and D-to-A converters, at no additional area or power consumption, were the other key enablers of this progress. 
Following the trend to ever higher integration levels today most data converters are embedded in a System-on-Chip together with a selection of RF, analog, and digital blocks, complete DSPs, µPs, or even MEMS. This defines another paradigm change, posing new chances and new challenges to the concept engineers and to the designers: now they have a complete system in their hands, with all chances for optimization, but also with the need to understand the complete system as well as the tradeoffs between the various blocks and solutions.

COURSE OBJECTIVES AND CONTENT
The objective of this course is to teach what is necessary to select and to design the right data converter under consideration of basic system aspects and tradeoffs.
We will brush up the basics of sampling, quantization, and Fourier transforms. We will look into a complete signal processing chain, discuss tradeoffs and show how to derive the requirements for the ADC. Based on figures of merit and a large database the application ranges and performance limits for the various converter architectures will be investigated. And we will spend a lot of time on understanding the concepts, as well as the practical aspects of the relevant converter architectures. Time encoding, i.e. replacing voltage levels by quantization along the time axis, will be introduced. Sigma-Delta Modulators, as the workhorse of communication ICs, will get extensive treatment. For each converter architecture, published examples will be analyzed.  The top level design of a Sigma-Delta-Converter will be demonstrated and the basic principles of data converter testing will be introduced. For a deeper understanding, the attendees will implement simple MATLAB routines for the evaluation of measured data. Finally, exemplary solutions will be discussed and given to the attendees.
Having all these topics covered by one speaker makes this a very compact and coherent course with high practical relevance.

WHO SHOULD ATTEND
This course is aimed at system and concept engineers who need to better know the role of the data converter in a system, the choices, the chances and the limitations. It also targets design engineers who wish not only to understand the theoretical and the practical aspects of the different converter topologies but also to get a view beyond the converter. Pre-requisites for the course are a basic understanding of semiconductor circuits and blocks together with some (limited) knowledge of analog circuit design. First experience with data converters is helpful.

Attendee equipment:
A pocket calculator is helpful for some of the exercises.
For the last day a notebook with appropriate software, MATLAB with Control System, Signal Processing Toolboxes*, or OCTAVE with Control, Signal, Missing-functions Toolboxes, is required to actively participate in the practical exercises. You will work in groups of 2 to 4 people.

Unfortunately we cannot offer the attendees a temporary MATLAB license, however, the freeware program OCTAVE** can as well be used to code and simulate m-files (but not mdl-files).

*    From The Mathworks, www.mathworks.com
**  http://www.gnu.org/software/octave and https://sites.google.com/site/guioctave/

Monday
During the first day, we will browse applications of data converters, brush up some theoretical background, learn the basic concepts and definitions underlying A-to-D conversion, and start looking into high speed A-to-D converters.

Applications of Data Converters

Theoretical Background

• Sampling
• Aliasing
• Quantization
• Discrete Fourier Transform

High Speed A-to-D Converter Concepts

• Definitions and Error Mechanisms
• FLASH
• Two-Step and Sub-ranging
• Folding
• Time Interleaved
• Pipelined

Tuesday
During the second day, we will continue with Nyquist type ADCs, studying power and/or area efficient implementations. Then figures of merit will be introduced. Derived by statistical evaluation of a large database, graphs will clearly show trends, application ranges and tradeoffs of the various A-to-D converter concepts. After that we will cover DAC architectures, implementations and end the day with the basics of Sigma-Delta-Converters. 

Efficient A-to-D Converter Concepts

• Algorithmic
• Successive Approximation
• Slope
• Asynchronous

Noise

• Thermal and 1/f Noise
• Noise Reduction: Chopping, Correlated Double Sampling

Figures of Merit, Statistics, Trends

D-to-A Converter Concepts

• Basics
• Resistor Based
• Switched Capacitor
• Switched Current
• Advanced Concepts
• Figures of Merit, Some Statistics

Oversampling and Noise Shaping Converters

• Delta Modulator
• Sigma-Delta ADCs: Basic concept and linear model
• Single Loop, Single Bit
• Higher Order
• Multi-Bit
• Feedback versus Feedforward Architecture
• Stability for Bounded and Unbounded Inputs

Wednesday
The third day, we will continue with sigma-delta-converters, discussing some complex implementations and some unusual applications. Aspects of modeling, design flow, and a look into Schreier's toolbox for synthesis and simulation conclude sigma-delta-converters. We will finish our examination of data converters by discussing the basic concept and implementations of time encoding converters.

Sigma-Delta Converters

• Unusual SDM Applications
• Bandpass and Complex SDM
• Cascaded (MASH)
• Continuous Time vs. Discrete Time
• Modeling, Design Flow
• Schreier's Toolbox
• PDM-Filter

Time Encoding

• Basics, PDM and PWM Signals
• Sigma-Delta DACs
• PWM Signal Generation - Class D Amplifiers
• Time-to-Digital Converter (TDC)

Thursday
The fourth day will start with an introduction to analog filters, some basic topologies and the need and the methods of filter tuning to overcome PVT variations. With this knowledge we will take another look into the signal processing chain from source to ADC, discuss tradeoffs and describe a methodology how to derive the ADC specification.  A practical example in Sigma-Delta converter synthesis and top-level simulation concludes the day. 

Filters

• Filter Characteristics
• Filter Implementation, Active Biquads
• Tuning

System Tradoffs

• VGA-Filter-Converter - how do I partition my system?

Practical Example

• Selection, Synthesis and Top Level Simulation of a Sigma-Delta Converter for a Digital Microphone

Friday
During the last day common converter test methods, strongly based on an IEEE standard for ADC test, will be explained. The attendees will receive a set of 'measured' data and program the core routines to evaluate them.

• DAC test
• ADC test

o   Histogram based test

o   FFT based test

• "Hands-on" Exercises (group work)
• Exemplary solutions

Said about the course from previous participants:
"Broad coverage of ADC and DAC with various concepts and architecture. Well-organized and introduced presentation."
"The course brings up new techniques and it gives a good overview of existing and future standards."
"Good mix between overview and deep information."
"Quite complete scope of different topics."
"Many references, clear overview, many examples and real circuits included, nice graphs, good slides - good reference course for the entire company!"