PAM Analysis

Meas. mode:
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With option PAM-N Analysis software, you can perform electrical and optical measurements on Pulse Amplitude Modulation (PAM4) waveforms. Measurements are available in both Oscilloscope and Eye/Mask modes. Jitter analysis can be made on PAM4 measurements in Jitter mode.

PAM Waveform
in Oscilloscope Mode
PAM Waveform
in Eye Mode


The following table shows some of the PAM4 features that are available. This is a partial listing to show the main tasks that you can perform.

PAM4 support at a glance
Feature Support
Yes Partial No
Compatible signal types
Common mode
Eye mode
Dedicated PAM4 measurements
(also measures NRZ signals)
Measurements on Eye Meas tab
Measurements on Adv Eye tab
(Requires option 401)
Mask testing
Oscilloscope mode
Dedicated PAM4 level measurements
Measurements on Time tab
Measurements on Amplitude tab
Jitter mode
Simulated waveforms
Math/Waveform signal processing functions

Autoscale and Signal-Type Detection

When an autoscale is performed, FlexDCA automatically identifies the signal type of all displayed channel, common mode, differential mode, and function waveforms. Signal types can be unspecified, NRZ, or PAM4. In certain situations, a PAM4 waveform may not be able to be automatically identified. For example, this can happen when the waveform's eye is nearly closed. If this happens, open the Signal Types tab of the PAM-N Analysis Setup dialog and manually specify PAM4. These settings are linked to the settings in the local dialog boxes.

The source type of waveform memories and eye memories is not autodetected, but can be manually set. If you save a waveform or color-grade gray-scale waveform to a file, the signal type is noted within the file: unspecified, NRZ, or PAM4. If the file is then loaded into waveform or color-grade gray-scale memory the signal type setting is loaded along with the data. Of course, you can always manually set the signal type in the Signal Types tab of the PAM-N Analysis Setup dialog.

For simulated modules, you can configure the simulated source waveform to be PAM4 or NRZ.

PAM measurements require FlexDCA version A.04.50 or later.