Continuous time linear equalization (ctle), Continuous time linear equalizer (ctle) – Teledyne LeCroy Eye Doctor II User Manual

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Operator's Manual

can be used as inputs to SDA II to perform eye diagram and jitter analysis. These are not used when
using equalization within SDAIII-CompleteLinQ, since equalization is simply a step in the overall serial
data analysis flow when using SDAIII-CompleteLinQ.

Note to SDAII Users: We strongly recommend that you use EyeDrClk as the explicit clock reference wave-
form in SDAII in order to properly analyze an unequalized signal in SDA II. SDA II cannot recover a clock
from a severely degraded signal; Eye Doctor II must recover the clock after equalizing the signal, and the
SDA II must use EyeDrClk to show the nearly closed eye.

For detailed information on training the equalizers in Eye Doctor II, see

How to Train Eye Doctor

II Equalizers

.

Continuous Time Linear Equalization (CTLE)

A first order Continuous Time Linear Equalizer (CTLE) is implemented in your Eye Doctor II software. The
reference equalization algorithm for PCI-Express 3.0 and for SuperSpeed USB is a first order CTLE. The
default settings for DC Gain and Boost for our implementation are the settings for SuperSpeed USB.

The CTLE is defined by DC Gain and the placement of 2 Poles and 1 Zero.

To use the CTLE:

1. Check the Enable checkbox in the Continuous Time Linear Equalizer (CTLE) section.

2. Ensure the Nominal Bit Rate is set correctly.

3. Specify the amount of Boost to use for equalization.

If you set the Boost on the Equalizer dialog, the DC Gain is unaffected and the higher frequency pole is
placed at the bit rate and the lower frequency pole at a fraction of the bit rate as used in SuperSpeed
USB. In order to set the requested boost, the Zero is also moved.

If you press Custom and then press the Edit / View CTLE Setup... you can set the DC Gain and the posi-
tions of the 2 Poles and 1 Zero (as follows).

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