Measurements and Testbenches

Analyze performance metrics of analog and mixed-signal systems

Analyze different foundation blocks and system-level models of mixed-signal systems using measurement blocks and testbenches. You can validate a block from the Mixed-Signal Blockset™ library, or you can validate your own customized blocks.

For PLL, use the measurement blocks to analyze performance metrics such as phase noise, reference and fractional spurs, aperture jitter, timing impairments, and lock time. Use block-specific testbenches to validate your customized blocks.

For ADC, use the measurement blocks to analyze key performance metrics such as aperture jitter, SNR, SINAD, noise floor, offset error, and gain error.

Use a system-level testbench to validate your PLL and ADC models.

Apps

Mixed Signal Analyzer

Analyze circuit simulation data

Blocks

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PLL Measurements and Testbenches

Lock Time Measurement	Measure time a PLL takes to reach target frequency within given tolerance
Phase Noise Measurement	Compute phase noise at specific frequency offset vectors
PFD and Charge Pump Testbench	Generic test environment for phase/frequency detectors and charge pumps
VCO Testbench	Validate voltage controlled oscillator (VCO) by measuring phase noise metrics or VCO characteristics
PLL Testbench	Validate PLL system by measuring operating frequency, lock time, and phase noise

ADC Measurement and Testbenches

ADC AC Measurement	Measure AC performance metrics of ADC output
ADC DC Measurement	Measure DC performance metrics of ADC output
ADC Testbench	Measures DC and AC performance metrics of ADC output

DAC Measurement and Testbenches

DAC DC Measurement	Measure DC performance metrics of DAC output
DAC AC Measurement	Measure AC performance metrics of DAC output
DAC Testbench	Measure DC and AC performance metrics of DAC output

Jitter, Timing, and Visualization

Clock Jitter Measurement	Measure jitter in periodic signals
Aperture Jitter Measurement	Measure aperture jitter of periodic signals
Timing Measurement	Measure period, frequency, duty cycle, rise time, fall time, and delay of a signal
Eye Diagram Scope	Display eye diagram of time-domain signal

Functions

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PLL Functions

`phaseNoiseMeasure`	Measure and plot phase noise profile of time or frequency-domain signal
`phaseNoiseToJitter`	Measure RMS phase jitter from phase noise data

Data Converter Functions

`inldnl`	Integral nonlinearity (INL) and differential nonlinearity (DNL) of data converters
`calibrateADC`	Remove offset and gain errors from ADC output
`calibrateDAC`	Compensate DAC input for offset and gain errors

Timing Functions

`timeDomainSignal2RiseTime`	Measure rise time of time domain signal
`timeDomainSignal2FallTime`	Measure fall time of time domain signal
`timeDomainSignal2DutyCycle`	Measure duty cycle of time-domain signal

Mixed-Signal Analyzer Functions

`adeinfo2msa`	Extract simulation data from Cadence to Mixed Signal Analyzer app
`msaSessionUpdate`	Update saved session of Mixed Signal Analyzer app

Featured Examples

Phase Noise at PLL Output

Predict the phase noise at the output of a phase-locked loop (PLL), simulate the PLL using the PLL Testbench, and compare the simulation results to theoretical predictions.

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Effect of Metastability Impairment in Flash ADC

Customize a flash Analog to Digital Converter (ADC) by adding the metastability probability as an impairment. You can measure the metastability probability impairment to validate your implementation. The example also shows the effect of metastability on the dynamic performance of the flash ADC. When the digital output from a comparator is ambiguous (neither zero nor one), the output is defined as metastable. The ambiguous output is expressed as NaN. This example model uses a MATLAB function block to add the metastability impairment to a flash ADC architecture. Another subsystem reports the metastability probability on the fly.

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Measuring Offset and Gain Errors in ADC

How offset error and gain error are calculated and how each affects the transfer curve of an ADC. Offset error and gain error characterize part of the linearity error in an ADC.

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ADC Linearity Measurement Using Histogram

Statistical measurement of ADC Linearity is popular in physical systems due to its noise tolerance and relative simplicity of implementation in a physical environment. This example covers problems inherent to statistical linearity measurements and some possible solutions for implementing these measurements in Simulink®.

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Analyze Clock Buffer Using Mixed Signal Analyzer

Use the Mixed Signal Analyzer app to analyze a clock buffer circuit and understand the effect of varying corner points using trend charts. You can also update the analyses with modified simulation data and export the results to a file.

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LDO Circuit Analysis Using Mixed-Signal Analyzer

Use the ‘Trend Chart’ plotting capability and ‘Update’ workflow feature of Mixed Signal Analyzer (MSA) app, in analyzing a Low Drop-Out (LDO) voltage regulator circuit.

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