DAC Testbench
Measure DC and AC performance metrics of DAC output
Libraries:
Mixed-Signal Blockset /
DAC /
Measurements & Testbenches
Description
The DAC Testbench block measures both DC and AC performance metrics of a DAC (digital to analog converter). DC performance metrics include offset error and gain error. AC performance metrics include signal-to-noise ratio (SNR), signal to noise and distortion radio (SINAD), spurious-free dynamic range (SFDR), effective number of bits (ENOB), and noise floor.
The DAC Testbench block generates the stimulus to drive the device under test (DUT) from the Stimulus tab. The setup parameters for validating the DUT are defined on the Setup tab. The target validation metrics are defined on the Target Metric tab.
You can use the DAC Testbench block to validate the DAC architecture models provided in Mixed-Signal Blockset™, or you can validate a DAC of your own implementation.
Examples
This example shows how to find the offset and gain errors of a binary weighted DAC block.
Open the model dac_dc_error. The model consists of a Binary Weighted DAC block and a DAC Testbench.
model = 'dac_dc_error';
open_system(model)
The parameters under the General tab of the Binary Weighted DAC are kept at their default values. The impairments are enabled in the Impairments tab, and the value of the offset error and gain error are set to 2 LSB and 1 LSB, respectively.
In the DAC Testbench block, the Measurement option is set to DC. In the Setup tab, the Autofill setup parameter button is used to automatically propagate the setup parameters from the DAC block. In the Target Metric tab, the Autofill target metric button is used to automatically set the target offset and gain errors from the DAC block. All other parameters are kept at their default values.
Run the simulation for 7.68e-04 s. The measured offset and gain errors are 2.00 LSB and 1.00 LSB, respectively.
The DAC transfer curve matches the best linear fit method. Using best fit method, maximum INL is -3.3e-4 LSB and maximum DNL is 4.6e-4 LSB.
This example shows how to find the AC performance metrics such as SNR, SINAD, SFDR, ENOB, noise floor and settling time of a binary weighted DAC block.
Open the model dac_ac_error. The model consists of a Binary Weighted DAC block and a DAC Testbench.
model = 'dac_ac_error';
open_system(model)
The parameters of the Binary Weighted DAC are kept at their default values.
In the DAC Testbench block, the Measurement option is set to AC. In the Setup tab, the Autofill setup parameter button is used to automatically propagate the setup parameters from the DAC block. Show spectrum analyzer during simulation option is also checked.
Run the simulation for 9e-3 s.
sim(model);
The measured AC performance metrics are displayed on the DAC Testbench block.
Ports
Input
Output
Parameters
References
Version History
Introduced in R2020a
