CTLE Operator

Instrument:
N1000A
N109x
Flex Apps:
FlexDCA
FlexRT
Meas. mode:
Scope
Eye
Jitter
TDR
Package License:
L-RND
Reference Rx Operator
CTLE Secondary Operator
TDECQ Secondary Operator
Linear Secondary Operator
DFE Secondary Operator

The Continuous Time Linear Equalizer operator is a transfer function defined by DC gain, zero frequency, and two or three poles. If you have a device-under-test that closes an eye diagram, you can use this operator to model a circuit that opens the eye diagram. To adjust these values, click on the operator icon which opens the dialog shown in this figure. Start with either selecting a Preset setup or by selecting the basic operator type with the Definition: 2 Pole, 3 Pole , or 2 Gain Stage CTLE.

The dialog's Display Setup tab is not displayed when the CTLE operator is setup as a secondary operator within the Reference Rx operator. Use the Reference Rx's Setup dialog to configure display settings.

Settings Available for Each CTLE Definition
Setting CTLE Definition
2 Pole 3 Pole 2 Gain Stage
DC gain ■ ■
Gdc (Low frequency gain, gDC) ■
Zero frequency ■ ■ ■
Low-frequency zero/pole ■
Pole Frequency ■ ■ ■
Noise Processing ■ ■ ■
Preset ■ ■ ■

Presets

Default User Folder

The default user data folder for presets files is \Presets\CTLE.

Presets allow you to save your dialog settings to a setup file. Recall a preset to instantly configure your Continuous Time Linear Equalizer to your specification. You can save as many presets as you need. The Preset list shows all of the factory provided presets as well as any that you have created. If you scroll to the end of the list and click the <Edit List> entry, the Edit CTLE Presets List dialog opens which allows you to reorder, delete, or rename items in the list. In the list, the names of factory provided presets includes the text (factory) which indicates that the entry cannot be edited.

Keysight Supplied CTLE Presets

  • CEI-112G-Linear (53GBd)
  • IEEE 802.3ck
  • CEI-112G-VSR-PAM4 (56GBd)
  • CEI-112G-VSR-PAM4 (58GBd)
  • IEEE 802.3bs CDAUI-8 (1 dB)
  • IEEE 802.3bs CDAUI-8 (1.5 dB)
  • IEEE 802.3bs CDAUI-8 (2 dB)
  • IEEE 802.3bs CDAUI-8 (2.5 dB)
  • IEEE 802.3bs CDAUI-8 (3 dB)
  • IEEE 802.3bs CDAUI-8 (3.5 dB)
  • IEEE 802.3bs CDAUI-8 (4 dB)
  • IEEE 802.3bs CDAUI-8 (4.5 dB)
  • IEEE 802.3bs CDAUI-8 (5 dB)
  • IEEE 802.3bs CDAUI-8 (5.5 dB)
  • IEEE 802.3bs CDAUI-8 (6 dB)
  • IEEE 802.3bs CDAUI-8 (6.5 dB)
  • IEEE 802.3bs CDAUI-8 (7 dB)
  • IEEE 802.3bs CDAUI-8 (7.5 dB)
  • IEEE 802.3bs CDAUI-8 (8 dB)
  • IEEE 802.3bs CDAUI-8 (8.5 dB)
  • IEEE 802.3bs CDAUI-8 (9 dB)
  • CEI-56G-VSR-NRZ (1dB)
  • CEI-56G-VSR-NRZ (2dB)
  • CEI-56G-VSR-NRZ (3dB)
  • CEI-56G-VSR-NRZ (4dB)
  • CEI-56G-VSR-NRZ (5dB)
  • CEI-56G-VSR-NRZ (6dB)
  • CEI-56G-VSR-NRZ (7dB)
  • CEI-56G-VSR-NRZ (8dB)
  • CEI-56G-VSR-NRZ (9dB)
  • CEI-56G-VSR-NRZ (10dB)
  • CEI-56G-VSR-NRZ (11dB)
  • CEI-56G-VSR-NRZ (12dB)
  • OIF CEI-28G-VSR (0dB)
  • OIF CEI-28G-VSR (1dB)
  • OIF CEI-28G-VSR (2dB)
  • OIF CEI-28G-VSR (3dB)
  • OIF CEI-28G-VSR (4dB)
  • OIF CEI-28G-VSR (5dB)
  • OIF CEI-28G-VSR (6dB)
  • OIF CEI-28G-VSR (7dB)
  • OIF CEI-28G-VSR (8dB)
  • OIF CEI-28G-VSR (9dB)

To save your settings, click the button. To recall your settings, click Load.

The Continuous Time Linear Equalizer operator requires a single-valued waveform, as opposed to an eye diagram. Be sure that your trigger setup results in a single-valued waveform at the input to this operator. This can be achieved using an external pattern trigger or by using pattern lock. If you are using an external pattern trigger, you may ignore this note.

Aliased Noise Processing

Process Spectrum Selection

The option Process Spectrum works by applying the transfer function of the filter to the power spectrum of the noise to determine the appropriate magnitude of the noise on the output signal.

By tracking the accumulated effects of the filtering operations, accurate noise processing can be done even when chaining operations as illustrated in the following figure. In addition to the sampled waveform, information about the acquisition channel and noise power spectrum are maintained in each signal and appropriately processed by each filter. The complete set of auxiliary information is also included when storing FlexDCA waveforms in the *.wfmx file format.

The default behavior of the Process Spectrum noise processing option is to use the noise power spectrum of the input signal. If the input signal is a sampling scope channel with SIRC active, this spectrum will be established by the measured hardware response of the channel. For other channels, the response will be assumed Gaussian with a 3 dB frequency corresponding to the nominal channel bandwidth. This behavior can be overridden by clearing the Track Input Response checkbox and manually entering a bandwidth. If this option is utilized the response will be presumed Gaussian with the selected 3 dB bandwidth.