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G.8263: Testing a Slave Clock using Paragon-neo

G.8263: Testing a Slave Clock using Paragon-neo

 

The ITU-T G.8263 standard specifies the required performance of packet-based equipment slave clock for frequency (PEC-S-F).

This article describes how to test such a clock using Paragon-neo.

Overview

A packet-based slave clock recovers frequency from PTP on an input port. This recovered frequency is then transferred to one or more frequency outputs e.g.

  • E1

  • T1

  • 2.048 MHz

  • SyncE

Hardware and Software Required

Your Paragon-neo should have the following options:

  • NEO-PTP-G.8275.2 (also enables G.8265.1)

  • NEO-E1-T1-Wander-Meas (if testing E1 or T1)

  • NEO-SyncE-Wander: SyncE Wander and ESMC (if testing SyncE)

  • appropriate interface option(s)

You must also have an external frequency reference of PRC (ITU-T G.811) quality or better.

Connecting your Slave to Paragon-neo

Paragon-neo will provide the frequency reference using PTP from the timeTransmitter port (port 1). This should be connected to the input port on your device under test (DUT).

You should connect your output to one of the following ports depending on what you are measuring:

  • SyncE: Port 2

  • E1/T1/2M: One of the wander measurement ports on the front of the Paragon-neo (unbalanced - E1 only; balanced T1 or E1).

    • image-20250716-094235.png

       

Configuring Paragon-neo for G.8263 Testing

For each test, you may need to configure your test set-up slightly differently. The test set-up is detailed separately for each of the tests below. Once you have configured your test set-up:

  1. Connect to your Paragon-neo using its IP address and a suitable browser.

  2. Select the PTP Preset

    image-20250716-094441.png

  3. Click Setup Ports and configure port 1 for the Line Rate and Interface to be used for the PTP input to the DUT.

  4. If testing SyncE, configure port 2 for the Line Rate and Interface carrying the output SyncE

  5. In the Clock Reference panel, enable the external reference Clock Source and configure it to match the source which you have connected to your Paragon-neo.

image-20250716-094737.png
image-20250716-095038.png

Ensure that the input is recognised by confirming the Reference Lock status LED is green:

image-20250716-095254.png

  1. Click the Run Apps button to open the measurement configuration page.

  2. Select timeReceiver under Test Mode.

  3. Select G.8265.1 Frequency Profile in the PTP profile selector menu. If you need to modify the configuration of the PTP to be generated (e.g source IP address, message rates, domain number), click the TT1 Config button then change the required parameters under the appropriate tab, e.g.

    image-20250716-110601.png

Section 5.1: Frequency Accuracy

image-20250718-082150.png

 

 

Stimulus

Pass / Fail Criteria

Notes

Free run

+/- 4.6ppm

Test duration is not specified in G.8263. Calnex suggests running for around 1000s

Measurement Setup

  • Connect the DUT to Paragon-neo as shown in the figure above. The configuration will depend on whether you are testing SyncE or E1/T1/2.048MHz

  • Ensure that Paragon-neo is configured as described in Configuring Paragon-neo for G.8263 Testing above

Measurement Process

  • In the Run Apps page, start Clock Wander Measurement (E1/T1/2.048MHz) and/or SyncE Wander Measurement (Port 2)

    image-20250716-101402.png

  • Click the CAT button on either app to view all captured data

  • Leave the capture running for 1000s, then click STOP on each of the apps.

  • Nvaigate to the CAT browser tab. if the results are not shown, click View Results and select the TIE/ESMC tab

  • In the right-hand pane under Frequency Offset Removal, the frequency offset is displayed. This should be less than +/-4.6ppm.

image-20250716-101735.png

 

Section 6.1: Noise Generation

image-20250718-082129.png

 

 

 

Stimulus

Pass / Fail

Notes

Ideal frequency reference (PTP)

MTIE mask

Test duration is not specified in G.8263. Calnex suggests running for around 10,000s

Measurement Setup

  • Connect the DUT to Paragon-neo as shown in the figure above. The configuration will depend on whether you are testing SyncE or E1/T1/2.048MHz

  • Ensure that Paragon-neo is configured as described in Configuring Paragon-neo for G.8263 Testing above

Measurement Process

  • In the PTP Emulation app, ensure the Paragon-neo timeTransmitter PTP generation is running. If not, click the START button

    image-20250716-102225.png

  • Allow the DUT some time to lock. The length of time required is dependent on your DUT.

  • Start Clock Wander Measurement (E1/T1/2.048MHz) and/or SyncE Wander Measurement (Port 2)

    image-20250716-101402.png

  • Click the CAT button on either app to view all captured data

  • Leave the capture running for 10,000s, then click STOP on each of the measument apps.

  • Navigate to the CAT browser tab. Click Select Metrics and enable MTIE under Clock Measurements

    image-20250716-102530.png

  • Click Calculate

  • Select the MTIE tab and in the right-hand pane under Masks, select G.8263 PEC-S-F Wander Gen Const. Temp.

    image-20250716-102624.png

  • The Pass / Fail result is indicated in the right-hand pane under Mask Status

image-20250716-102647.png

  • If no further testing is required, stop the PTP generation in the PTP Emulation app.

Section 7.1: Noise Tolerance

image-20250718-082239.png

 

 

Stimulus

Pass / Fail

Notes

Noise pattern

The PEC-S-F must:

  • Not cause the packet timing signal fail (PTSF- unusable) signal to be triggered (this is for further study)

  • Not cause the clock to go into holdover

  • Maintain the clock within prescribed performance limits

 

Measurement Setup

  • Connect the DUT to Paragon-neo as shown in the figure above. The configuration will depend on whether you are testing SyncE or E1/T1/2.048MHz

  • Ensure that Paragon-neo is configured as described in Configuring Paragon-neo for G.8263 Testing above

Measurement Process

image-20250716-104744.png

  • Load the appropriate imported impairment profile for both the forward and reverse directions by clicking on each of the Load buttons in turn, selecting the relevant pattern in the resulting window. If no suitable impairment files are displayed, follow the instructions above to obtain and/or import them onto your instrument.

  • In the PTP Impairments (Port1) app, click IMPAIR to start applying the impairment. (note that the PTP Generation is not running yet; this step is taken to ensure that the impairment will be applied immediately on starting that generation).

  • In the PTP Emulation app, click the START button to start PTP generation.

image-20250716-102225.png

  • Allow the DUT some time to lock. The length of time required is dependent on your DUT.

  • Start Clock Wander Measurement (E1/T1/2.048MHz) and/or SyncE Wander Measurement (Port 2)

  • Leave the capture running until the impairment has stopped and then click STOP on each of the measurements.

  • Navigate to the CAT browser tab. Click Select Metrics and enable MTIE under Clock Measurements

    image-20250716-102530.png

  • Click Calculate

  • Select the MTIE tab and in the right-hand pane under Masks, select G.8261.1 PEC-S-F Wander Limit Case 3

    image-20250716-103549.png

  • The Pass / Fail result is indicated in the right-hand pane under Mask Status

At no point during the test should the DUT have gone into hold-over or have triggered the PTSF-unusable signal.

What tests can I run and why would I choose them?

ITU-T G.8263 Appendix I.2 details the Test methodologies as well as a description of what types of tests/patterns could be used:

 

 

Testing using methods 1 and 2 is mandatory; method 3 (single sinusoidal waveform) is optional but may be useful in studying the detailed behaviour of the DUT.

Patterns to create these using Paragon-neo are available from the Calnex website, with each using a 64pkt/s rate:

Type

Forward Pattern

Reverse Pattern

Method 1 - Flicker Noise

flicker_gamma_eqn_24h_fwd_to_1588_V2_NEW.cpd

flicker_gamma_eqn_24h_rev_to_1588_V2_NEW.cpd

Method 2 - Combined sinusoidal waveforms

HRM1_Sum_AvePDVadd_50us_64pps_60ks_fwd_1588_V2_NEW.cpd

HRM1_Sum_AvePDVadd_75us_64pps_60ks_fwd_1588_V2_NEW.cpd

HRM1_Sum_AvePDVadd_150us_64pps_60ks_fwd_1588_V2_NEW.cpd

HRM1_Sum_AvePDVadd_50us_64pps_60ks_rev_1588_V2_NEW.cpd

HRM1_Sum_AvePDVadd_75us_64pps_60ks_rev_1588_V2_NEW.cpd

HRM1_Sum_AvePDVadd_150us_64pps_60ks_rev_1588_V2_NEW.cpd

Method 3 - single sinusoidal waveform

Sin_145us_T1ks_Power-law_-0.5_64pps_64ks_fwd_to_1588_V2_NEW.cpd

Sin_145us_T2ks_Power-law_-0.5_64pps_64ks_fwd_to_1588_V2_NEW.cpd

Sin_145us_T4ks_Power-law_-0.5_64pps_64ks_fwd_to_1588_V2_NEW.cpd

Sin_145us_T8ks_Power-law_-0.5_64pps_64ks_fwd_to_1588_V2_NEW.cpd

Sin_145us_T16ks_Power-law_-0.5_64pps_64ks_fwd_to_1588_V2_NEW.cpd

Sin_145us_T200s_Power-law_-0.5_64pps_64ks_fwd_to_1588_V2_NEW.cpd

Sin_145us_T500s_Power-law_-0.5_64pps_64ks_fwd_to_1588_V2_NEW.cpd

Sin_145us_T86400s_Power-law_-0.5_64pps_86400s_fwd_to_1588_V2_NEW.cpd

 

Sin_145us_T1ks_Power-law_-0.5_64pps_64ks_rev_to_1588_V2_NEW.cpd

Sin_145us_T2ks_Power-law_-0.5_64pps_64ks_rev_to_1588_V2_NEW.cpd

Sin_145us_T4ks_Power-law_-0.5_64pps_64ks_rev_to_1588_V2_NEW.cpd

Sin_145us_T8ks_Power-law_-0.5_64pps_64ks_rev_to_1588_V2_NEW.cpd

Sin_145us_T16ks_Power-law_-0.5_64pps_64ks_rev_to_1588_V2_NEW.cpd

Sin_145us_T200s_Power-law_-0.5_64pps_64ks_rev_to_1588_V2_NEW.cpd

Sin_145us_T500s_Power-law_-0.5_64pps_64ks_rev_to_1588_V2_NEW.cpd

Sin_145us_T86400s_Power-law_-0.5_64pps_86400s_rev_to_1588_V2_NEW.cpd

 

Section 8.1: Holdover

image-20250718-082251.png

 

Stimulus

Pass / Fail

Notes

Loss of reference (following period of lock)

TIE Mask

Test duration is not specified in G.8263. Calnex suggests running for around 10,000s

Measurement Setup

  • Connect the DUT to Paragon-neo as shown in the figure above. The configuration will depend on whether you are testing SyncE or E1/T1/2.048MHz

  • Ensure that Paragon-neo is configured as described in Configuring Paragon-neo for G.8263 Testing above

Measurement Process

  • In the PTP Emulation app, ensure the Paragon-neo timeTransmitter PTP generation is running. If not, click the START button

    image-20250716-102225.png

  • Allow the DUT some time to lock. The length of time required is dependent on your DUT

  • Start Clock Wander Measurement (E1/T1/2.048MHz) and/or SyncE Wander Measurement (Port 2)

  • Disconnect the ethernet cable from port 1 of Paragon-neo

  • Leave the capture running for 10,000s and then click STOP on each of the measurements.

  • Navigate to the CAT browser tab, select the TIE tab and in the right-hand pane under Masks, select G.8263 PEC-S-F Long-Term Holdover Const. Temp.

  • Adjust the Data Analysis Range so that the mask is aligned with the point at which the DUT begins to go into hold-over. This can either be done by moving the vertical range bars on the graph or by typing the range in the right-hand pane under Parameters

    image-20250717-134038.png

  • The Pass / Fail result is indicated in the right-hand pane under Mask Status