M809256CA Receiver Conformance Test Application for OIF-CEI 4.0

Introduction

Keysight M809256CA is an automated receiver test solution implementing the Channel Operating Margin (COM) and Stressed-Eye methods for OIF CEI-56G-VSR, MR & LR PAM4 interfaces.

Key Features

• Supported standards include the following:

o Clause 16 OIF-CEI 56G-VSR-PAM4 Very Short Reach Interface

o Clause 17 OIF-CEI 56G-MR-PAM4 Medium Reach Interface

o Clause 21 OIF-CEI 56G-LR-PAM4 Long Reach Interface

• Guided setup, automated stress signal calibration and conformance measurement

• HTML test report

• Data analytics enabled

• Choose between Node-locked, Transportable, Network, USB-dongle license types of the Perpetual License Term

Description

The M809256CA conformance receiver test application is designed to assist and simplify the stress signal calibration used for testing the inputs of CEI-56G-VSR/-MR/-LR PAM4 electrical interfaces using a Keysight M8040A 64Gbaud Higher Performance BERT and a Keysight Digital Communication Analyzer (DCA) Oscilloscope. Newly supported hardware includes Keysight N109xx series DCA-M oscilloscopes as well as UXR series real-time oscilloscope. The value of the test application helps to reduce user interaction to a minimum and performs all required calibration routines and compliance testing automatically by remote controlling all required instruments. A wide range of hardware configuration is supported, thus protecting your investment.

Calibrations and Tests Covered by M809256CA Receiver Test 

Application CEI-56G-VSR (host or module)

OIF CEI-56G-VSR PAM4 defines the stress signal through a mated host compliance board (HCB) and module compliance board (MCB) connection. Both the receiver side as well as the transmitter side have equalization capabilities. The definition of the stress signal assumes an optimized link. Therefore, the transmitter of the receiver test equipment as well as the receiver of the signal measurement device must be optimized for the given stress channel. This must be done iteratively for each test setup. The standard requires the transmitter equalization (TxEQ) to be kept as small as possible to increase the stress on the device under test’s receiver (DUT RX). If performed manually, this procedure is very time consuming. However, the M809256PB Receiver test application performs this task automatically.

Example setup for VSR Host input stress eye calibration

• MCB and HCB

• X-Talk Generator Data Out 2 P/N to TPI P/N of MCB

• Termination via 50 Ohm to TPIa P/N of HCB

• Victim Generator Data Out 1 P/N to TP4aP/N of HCB

• Oscilloscope CVH1/CH2 to TP4 P/N of MCB

All calibration steps are automated. The test application prompts the user whenever user interaction is required for connecting or modifying the test setup. Detailed connection diagrams and instructions are provided by the test application.

OIF CEI-56G-MR/-LR PAM4

Both 56G-LR and -MR test procedures rely on the Channel Operating Margin (COM) method2. COM has been first introduced to measure the performance margin of a channel and then extended to digital systems. Interoperability of digital receiver can be expressed in terms of COM requirements. COM is calculated out of channel 4-ports S-parameters (for victim and aggressor lanes) as well as the noise and equalization functionality of the considered transmitter and receiver. The resulting COM metric is the ratio of the signal amplitude (after equalization) to the noise and cross-talk peak-to-peak amplitude measure during a time interval depending on the target BER. 

OIF CEI-56G-MR/-LR PAM4 receiver test calibration procedure consists of three steps3:

1. S-parameter measurements (only once per system)

2. System calibration: Calibrate the equipment used to generate the victim transmitter and the broadband noise

3. COM-related calibration: Following steps are performed to complete the COM model

a. Check channel characteristics (S-parameters)

b. Measured Tx characteristics (jitter & electrical characteristics)