Topics
- Two signal levels
- Information storage with digital signals
- Serial and parallel data
- Other uses for digital signals
- Control signals
- Number storage
- Digital Devices
- Digital Test Systems
- Functional testing
- Logic Levels
- Parametric Testing
- DC Measurements
- AC Measurements
- Vector
Sequencing
Topics
- Infinite signal levels
- The Time aspect of analog signals
- Analog
Circuitry
Topics
- "Rack and Stack"
- Traditional Analog ATE
- Mixed
signal devices
Topics
- Waveform Digitizer
- Information Loss When Digitizing
- Truncation Error
- Quantization Error
- Slew Rate Error
- Jitter Error
- Waveform Generator
- Digital
Signal Processor
Topics
- Introduction
- Logarithms and exponents
- Logarithm bases and uses
- Common log
- Natural log
- Log base 2
- Properties of logarithms
- Decibels (dB)
- Time and Frequency
- Periodic Motion
- Rotating vector
- Converting angle q to frequency and time
- RMS value of a sinusoid
- Phase and the cosine function
- Time to frequency translation
- Frequency domain plot of DC
- Frequency domain plot of a sine wave
- Frequency domain plot of an impulse
- Fourier series
- Dirichlet conditions
- Calculating the sine and cosine components
- Complex numbers
- The j operator
- The complex plane
- Conversion
between polar and rectangular
Creating, Taking and Processing Samples
Topics
- Limits of Sampling
- Shannon's theorem
- Nyquist's theorem
- Periodicity
- What does a sample set represent?
- Converting a time sample set to frequency
- Discrete Fourier transform (DFT)
- Fast Fourier transform (FFT)
- Spectral replication and aliasing
- Replication
- Aliasing
- Prevention of aliasing errors
- Leakage
- Incomplete sample set
- Time sample windowing
- Coherent Sampling
- What is coherent sampling?
- Why sample coherently?
- Coherency relationships
- Fs, N, Ft and M
- UTP, Fourier Frequency, frequency bins and resolution
- Mutually prime N and M assures unique sample points
- Converting frequency data to time samples
- The Inverse FFT (IFFT) algorithm
- Uses for the IFFT
- Limitations
of using the IFFT
Specifications of Analog and Digital Devices
Topics
- Digital Device Specifications
- Analog Circuit Specifications
- Op Amp specifications
- VIO—Input offset voltage
- IIB—Input bias current
- IIO—Input offset current
- CMRR—Common mode rejection ratio
- PSRR—Power supply rejection ratio
- GBW—Gain bandwidth
- THD—Total harmonic distortion
- Noise
- SR—Slew rate
- ts—Settling Time
- Comparator Specifications
- Response Time
- Filter Specifications
- Bandwidth (BW)
- Quality Factor (Q)
- Center Frequency (f0)
- Settling
time
Mixed Signal Device Specifications
Topics
- D/A Converter Specifications
- Full scale range
- Offset error
- Gain error
- LSB size
- Differential nonlinearity
- Monotonic
- Integral nonlinearity
- Accuracy
- Total harmonic distortion (THD)
- Signal to noise ratio (SNR)
- Maximum conversion rate
- Settling
time
Topics
- Full scale range
- Offset error
- Gain error
- LSB size
- Differential nonlinearity
- No missing codes
- Integral nonlinearity
- Accuracy
- Total harmonic distortion (THD)
- Signal to noise ratio (SNR)
- Conversion time
- Aperture time
- Aperture jitter
- Transition
Noise
Calculation of SINAD, SNR, THD and IM
Topics
- Signal to Noise and Distortion (SINAD or SNDR)
- Total Harmonic Distortion (THD)
- Signal to Noise Ratio (SNR)
- Intermodulation
Distortion (IM)
Digital to Analog Converter Static Parameters
Topics
- Measuring offset and gain errors
- Offset Error
- Attenuation is your friend
- Gain Error
- Measuring DNL and INL
- Making one DNL measurement
- Making all DNL measurements
- The DNL Test
- Testing for INL
- Considerations for testing DACs with an LSB < 5mV
- Temperature Effects
- Reference Signal
- Internal Reference
- External Reference
- Current vs. voltage output
- Averaging and repeatability
- Synchronization
Issues
Analog to Digital Converter Static Parameters
Topics
- Unique ADC testing problems
- Transitions, zero scale, full scale and LSB size
- Measuring transition points
- Using a D/A to step the ADC input
- Using an integrator loop
- Using an intelligent feedback loop
- The digital side of ADC testing
- Offset error
- Gain error
- DUT noise, system noise and averaging
- DUT noise
- System noise
- DNL and INL test methods
- Finding the "center of code"
- Static DNL
- Static INL
- Histogram ADC test methods
- Ramp histogram
- Sine histogram
Digital to Analog Converter Dynamic Parameters
Topics
- Measuring SINAD, THD, SNR, IM
- Generating the DUT output signal
- Calculating the desired output signal as an array of points
- Using sine wave equation
- Using Inverse FFT
- What to do with the list of codes
- Filtering the output signal
- Using a Waveform Digitizer to capture the DAC output
- Conditioning the analog signal for the waveform digitizer
- Digitizing the (filtered) analog signal
- Calculating the result parameters
- Creating a Spectrum Graph
- Synchronization
Issues
Analog to Digital Converter Dynamic Parameters
Topics
- Dynamic parameters
- Creating an input signal
- Adjusting for zero and full scale
- Input signal purity filtering
- Input signal anti–aliasing
- Capturing the digital output data
- Acquiring and holding the input signal
- An ADC with no track and hold
- Adding track and hold
- Dynamic impedance problems
- Coherent sampling revisited
- Normal sampling
- Undersampling
- SINAD, THD, SNR and IM
- DUT noise, system noise and averaging
- Effective
Number Of Bits (ENOB)
Summary of General Test Issues
Topics
- The Biggest Problem in Mixed Signal Test Development
- Does the measurement reflect the conditions of the DUT or the test system?
- Look for the obvious errors first
- There’s no such thing as ground!
- Amplifiers amplify noise too
- Capacitance is generally your enemy, and it’s always there
- Friendly capacitance—power supply decoupling
- The test system must be 10 times better than the DUT
- The DUT power supply can cause measurement errors
- Unexpected things can affect measurement results
- Location of the tester’s earth ground connection
- An ungrounded DUT package case
- External noise from RF or magnetic sources
- Light
- Humidity
