Module 1 – Introduction to Mixed Signal Testing
Overview of Mixed Signal Testing
Static Performance
Dynamic Performance
Digital Signals
Digital Test Systems
Analog Signals
Analog Test Systems
Mixed Signal Devices
Converters
Datacom Devices
Telecom Devices
Mixed Signal Test Systems
Waveform Digitizer
Waveform Generator
Digital Signal Processor
Mixed Signal Device Specifications
Digital Specifications
Analog Specifications
Input Offset Voltage
Input Bias Current
Input Offset Current
Common Mode Rejection
Power Supply Rejection
Gain Bandwidth
Noise
Signal-to-Noise Ratio
Harmonic Distortion
Slew Rate
Settling Time
Filters
Filter Types
Filter Performance
Filter Specifications
Putting It All Together
A Mixed Signal Test Example
Representative Mixed Signal Test System Specifications
Laboratory Exercises
Chapter 1 Questions
Chapter 2 Questions
Module 2 – Testing Static Performance Parameters
Digital to Analog Converter Static Measurements
DAC Static Specifications
Resolution
Gain and Offset
Differential and Integral Non-Linearity
Least Significant Bit
Monotoncity
Test System Configuration for DAC Static Parameter Tests
Digital Signal Input
Capturing an Analog Output
Example DAC Data Sheet
DAC Device Architecture Considerations
Different DAC Architectures
Architectural Test Considerations
Measurement Techniques
Using Meters
Using Waveform Digitizers
Analog to Digital Converter Static Measurements
ADC Static Specifications
LSB Size
Full Scale Range
Offset and Gain
Code Transitions and Code Widths
Differential and Integral Non-Linearity
No Missing Codes
Transition Noise
Test System Configuration for ADC Static Tests
Analog Input Signal
Capturing a Digital Output Signal
Example ADC Data Sheet
Histogram Testing for DNL and INL
ADC Device Architecture Considerations
Different ADC Architectures
Architectural Test Considerations
Laboratory Exercises
Chapter 3 Questions
Chapter 4 Questions
DSP Lab Exercise – Examining Noise in the Time Domain
Module 3 – Mixed Signal Mathematics and Sampling Theory
The Mathematics of DSP
Logarithms and Exponents
Decibels (dB)
Time and Frequency
Periodic Motion
Root-Mean-Square Calculations
Time to frequency translation
Fourier series
Dirichlet conditions
Complex numbers
Conversion between polar and rectangular
Sampling Theory
Limits of Sampling
Shannon’s theorem
Nyquist theorem
Periodicity
Converting a time sample set to frequency
Discrete Fourier transform (DFT)
Fast Fourier transform (FFT)
Sampling Pitfalls and Solutions
Spectral replication and Aliasing
Prevention of aliasing errors
Leakage
Time sample windowing
Coherent Sampling
Fs, N, Ft and M
UTP, Fourier Frequency, frequency bins and resolution
The Inverse FFT (IFFT) algorithm
Laboratory Exercises
Chapter 5 Questions
Chapter 6 Questions
Lab Exercise – Creating and examining a Fourier series
Lab Exercise – Sampling
Lab Exercise – Creating a Frequency Spectrum from Digitized Samples
Lab Exercise – The Effects of Aliasing in the Frequency Domain
Lab Exercise – Inverse Fourier Transform Time Sample Generation
Module 4 – Testing Dynamic Performance Parameters
Digital to Analog Converter Dynamic Parameters
Measuring SINAD, THD, SNR, IM
Intermodulation Distortion
Multitone Generation
Generating the DUT input signal
Calculating the desired signal as an array of points
Using a sine wave equation
Using an Inverse FFT
What to do with the list of codes
Using a Waveform Digitizer to capture the DAC output
Conditioning the analog signal for the waveform digitizer
Filtering the output signal
Digitizing the (filtered) analog signal
Calculating the result parameters
Undersampling
Analog to Digital Converter Dynamic Parameters
Dynamic parameters
Creating an input signal
Adjusting for zero and full scale
Input signal filtering
Acquiring and holding the input signal
Dynamic impedance problems
Capturing the digital output data
Coherent sampling revisited
SINAD, THD, and SNR
Spurious Free Dynamic Range
DUT noise, system noise and averaging
Effective Number Of Bits (ENOB)
Sparkle Codes
Sine Histogram Technique
Laboratory Exercises
Chapter 7 Questions
Chapter 8 Questions
Lab Exercise – Creating DAC inputs for a sine wave
Lab Exercise – Digitizing a Sine Wave
Lab Exercise – Coherently sampling a sine wave
Lab Exercise – Undersampling with the beat frequency method
Lab Exercise – Undersampling using the Envelope method
Module 5 – Applying Mixed Signal Test Concepts in the Real World
Oversampling to Improve Dynamic Range
Delta Sigma Conversion and Test
How Delta Sigma Conversion Works
Self Tones
Multirate conversion
Transmission Lines and Signal Termination
Lumped vs. Distributed Circuits
Termination Techniques
Jitter in Mixed Signal Test
Jitter Effect on Coherence
Jitter Effect on SNR
Minimizing Clock Jitter
Measuring Jitter with Mixed Signal Instruments
Mixed Signal Fixture Design
Parasitic Circuit Elements
Signal Coupling
Capacitors
Sockets
Layout Suggestions
General Test Issues
Does the measurement reflect the conditions of the DUT or the test system?
Noise in the test environment
Ground Issues
Current Paths
Power Supplies
Averaging and Repeatability
Testing Mixed Signal SOCs – An Example