G.8262 SyncE Conformance Testing

Calnex Solutions Ltd Page 1 of 58

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Application note CX5001

G.8262 SyncE Conformance testing

1. Hardware and Software required ............................................................................................. 2

2. Connecting an EEC to the Paragon-X ..................................................................................... 3

3. How to Configure the Paragon-X for ALL G.8262 Tests .......................................................... 5

4. Measuring Frequency Accuracy – G.8262 Section 6 ............................................................... 9

5. Pull-in, Hold-in and Pull-out ranges – G.8262 Section 7 ........................................................ 11

6. Wander (Noise) Generation – G.8262 Section 8 ................................................................... 15

7. Jitter Generation – G.8262 Section 8.3 .................................................................................. 19

8. Wander (Noise) Tolerance – G.8262 Section 9 ..................................................................... 23

9. Jitter Tolerance – G.8262 Section 9.2 ................................................................................... 29

10. Wander (Noise) Transfer – G.8262 Section 10 ...................................................................... 35

11. Phase Transient Response – G.8262 Section 11 .................................................................. 44

12. Appendix 1 - G.8262 Testing; Practical interpretation guidance............................................. 54


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1. Hardware and Software required

Paragon-X

o Option 110 – GbE electrical and Optical

o Option 111 – 10GbE interface (optional)

o Option 120 – Delay and Header Capture

o Option 213 – Sync-E measurements

o Option 223 – MTIE/TDEV internal wander generation

o Option 207 or 217 Jitter generation & measurement for 100M and 1GbE

o Option 208 or 218 Jitter generation & measurement for 10GbE (optional)

o Paragon- X Software X.10.14 or higher

Synchronisation (Reference) Frequency Source


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2. Connecting an EEC to the Paragon-X

The front panel of the Paragon-X provides the following interfaces for testing:

1. 100MbE Electrical or Optical (SGMII SFP)

2. 1GbE Electrical or Optical (SFP) – with option 110 fitted

3. 10GbE Optical (XFP or SFP+) – with option 111 fitted

Paragon-X Front Panel Connections

10GbE Port 1

100MbE/1GbE Port 1

10GbE Port 2

100MbE/1GbE Port 2

Status Display

PC Controller Port


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The Paragon-X accepts the following reference clocks which should be applied to one of the

Reference Inputs on the back panel:

1. 2.048MHz

2. 10MHz

3. E1 (2.048Mb/s)

4. DS1 (T1) (1.544Mb/s)

Fig. 1 Paragon-X Reference Inputs (Back Panel)

There are two reference inputs

BNC with 75Ω impedance (the connector on the left in the figure).

Bantam connector with 100Ω impedance.

o 3 pole bantam jack o 4.39mm Diameter o Tip; Positive, Ring; Negative, Sleeve; Ground


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3. How to Configure the Paragon-X for ALL G.8262 Tests

a) Verify your physical connections have been completed per section 2.

b) Start the Paragon-X GUI

c) Select the “Operating Mode” button.

d) Select “Sync-E” then select “Close”

e) Click

f) Select “Tx + Rx mode”


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g) Verify that the “SyncE Clock Rx > Tx is not checked

h) Select the reference clock source.

i) Select the line rate and Electrical/Optical (100M/1GbE/10GbE).

Note: If using SFP’s, XFP’s or SFP+’s, BOTH Port 1 and Port 2 optical transceivers must be

inserted into the Paragon-X.

j) Select the “Close” button to close the Physical Settings window, and then select “Close” again to

close the setup interface window.

Note: once you have selected Sync-E mode, the Paragon-X GUI will display “SYNCE LOCK” as

grey (This verifies that the SyncE Rx > Tx box is unchecked, meaning that the Paragon-x is using

its internal or external clock. If the SyncE Rx>Tx box were checked in the required Tx+Rx mode,

there would be no clock).


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ESMC Generation

Ethernet Synchronisation Message Channel (ESMC) is a Point to Point Protocol in which each

EEC generates and terminates an ESMC PDU. This ESMC PDU is normally transmitted once per

second on the Slow Protocol Channel and contains the Quality Level (QL) of the associated clock

. The receiving EEC uses this QL to select the best quality clock. The EEC then regenerates the

ESMC PDU with the appropriate QL TLV value to indicate the quality of the clock being

transmitted to the next EEC.

If the EEC supports ESMC, it is possible for the Paragon-X to use this functionality to indicate if

an EEC switches clock reference or goes into holdover.

The Paragon-X can generate ESMC messages on both Ports 1 and 2. For G.8262 conformance

testing, ESMC messages are generated on Port 2 with a user- defined Quality Level (QL) such as

PRC.

a) Generate ESMC messages by selecting the button. The following window will

open.

b) Check the box “Enable TX+Rx Mode”. This sets the instrument in terminate mode.


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c) Select “Port 2” tab (the output from the Paragon and input to EEC)

d) Select “SSM code” QL-PRC, which tells the EEC that the clock from the Paragon-X is of PRC

quality.

e) Set IPG (inter-packet gap) rate to 1000mS. This makes the instrument send ESMC packets once

per second.

f) Click and then

g) The ESMC Generation button will go red to indicate the Paragon-X is generating ESMC packets.

After any setup changes to the Paragon-X, please ensure the EEC has had time to settle

before making any measurements


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4. Measuring Frequency Accuracy – G.8262 Section 6

Input Stimulus Pass/Fail Criteria Notes

EEC Option 1

Free run +/- 4.6 ppm

Recommend to test for

an hour, longer if close

to limits

EEC Option 2

Hold over +/- 4.6 ppm

Recommend to test for

an hour, longer if close

to limits

Measurement Setup

a) Connect the EEC to Paragon-X as shown above

b) Set up the Paragon-X GUI as per Section 3.

Measurement Process

a) Select the “Start Capture” button to start measurement.

b) To stop the measurement after a pre-defined period for running the test, select “Stop Capture”

button.


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c) Paragon-X will provide the ppm frequency accuracy at the bottom of the graph in red text (as

shown in the screen shot at the top of the next page).


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5. Pull-in, Hold-in and Pull-out ranges – G.8262 Section 7

Pull–in Range (G.8262 Section 7.1) The Pull-in range is defined as the largest offset between a slave clock's reference frequency and

a specified nominal frequency, within which the slave clock will achieve locked mode.


EEC

Option 1

and

EEC

Option 2

Apply a large Frequency

offset ensuring EEC is in

holdover. Reduce offset

until EEC locks.

EEC starts unlocked with large offset applied

EEC locks before offset reaches +/- 4.6ppm

Lock can also be

monitored by using

ESMC (if supported)

Hold–in Range (G.8262 Section 7.2) Hold-in range is defined as the largest offset between a slave clock's reference frequency and a

specified nominal frequency, within which the slave clock maintains lock as the frequency varies

arbitrarily slowly over the frequency range.


EEC

Option 1 Not Applicable

EEC

Option 2

EEC is locked to the clock

from the Paragon-X. The

Frequency is then offset

to +/-4.6ppm

EEC should remained locked at an offset at +/-4.6ppm

Lock can also be

monitored by using

ESMC (if supported)


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Pull–out Range (G.8262 Section 7.3) Pull-out range is defined as the offset between a slave clock's reference frequency and a

specified nominal frequency, within which the slave clock stays in the locked mode and outside of

which the slave clock cannot maintain locked mode, irrespective of the rate of the frequency

change.


EEC

Option 1




until the EEC unlocks

EEC should remain locked at an offset at +/-4.6ppm but lock should extend beyond this.

G.8262 states this is for

further study

EEC


Measurement Setup

a) Connect the EEC to Paragon-X to EEC as shown in the diagram at the beginning of this section

b) Set up the Paragon-X GUI as per Section 3, including setting up ESMC with QL=PRC if using

ESMC to monitor which clock the EEC is locked to.

Measurement Process

a) select the “Start Capture” button to start measurement.

b) Select the “Wander” button. Select the “Frequency Offset” tab


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c) In the Frequency Offset window, add the Frequency Offset required and click the “Apply Offset”

button

d) To remove the Frequency Offset and return it back to 0ppm click the “Remove Offset”

button

e) To stop the measurement after a pre-defined period for running the test, select “Stop Capture”

button.

f) The Paragon-X TIE graph indicates if the EEC is in or out of lock as shown in the screenshot

below


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6. Wander (Noise) Generation – G.8262 Section 8

Input Stimulus Pass/Fail Criteria

Notes

(G.8262 masks)

EEC Option 1

(Constant Temp)

- Locked Mode

- Wander Free reference

- Constant temperature

MTIE & TDEV Pass/Fail masks shown in G.8262 Section 8.1.1

MTIE – Table 1/ Figure 1

TDEV – Table 3/ Figure 2

EEC Option 1

(Temp effects)

- Locked Mode


- Temperature effects

MTIE Pass/Fail masks shown in G.8262 Section 8.1.2.


TDEV – G.8262 states

for further study

EEC Option 2

(Constant Temp)

- Locked Mode






G.8262 Section 8.2 also mentions measurements in Non-locked mode and refers to section 11.2

“Long-term phase transient response (Holdover)” and will not be covered in this section.

Measurement Setup a) Connect the EEC to Paragon-X to EEC as shown in the diagram at the beginning of this section

b) Set up the Paragon-X as described in section 3, including setting up ESMC with QL=PRC if

using ESMC to monitor which clock the EEC is locked to.

Measurement Process

a) Select the “Start Capture” button to start measurement.


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b) To stop the measurement, select “Stop Capture”. . It is suggested that the test

should run for approx 3,000 seconds

c) The graph will show the captured TIE

d) To display the MTIE and TDEV graphs click on the bottom right hand side of the

graph and then “MTIE/TDEV Analysis” from the displayed menu.

e) A separate window will open showing the TIE in graphical form at the top, with an MTIE/TDEV

graph at the bottom.


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f) The MTIE/ TDEV analysis can be carried out against the G.8262 masks for Wander

Generation which can be selected from the measurement mask pull down selection in the left

hand window.

g) Pass/Fail indication against the masks is shown also in this left hand window and will have a

green background for “Mask Pass” and a red background for “Mask Fail”


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7. Jitter Generation – G.8262 Section 8.3


All Sync-E

interface

rates

None, unless

device requires

packet stream to

function

Output jitter <=0.5UIpp in 60-second window, as G.8262 8.3 table 6

i. Measurement

filter bandwidths

specified in

G.8262.

ii. G.8262 treats 1G

electrical as “for

further study”.

Calnex

recommends to

use the same

0.5UIpp limit until

further defined by

ITU.

a) Operating mode must be set to Sync-E, and Sync-E jitter selected as a measurement.


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Interface rate choice will then automatically be restricted to 1Gbit/s (Electrical or optical) or

10Gbit/s (100Mbit/s excluded).

For 10Gbit/s optical, device type is automatically restricted to SFP+ (XFP excluded). Normally, the operating configuration is set to Tx+Rx mode.

b) Configure capture contains a jitter measurement threshold setting. If the checkbox is ticked, the

capture (result) screen will indicate pass/fail of the peak-peak jitter result currently selected,

relative to this limit. Note that the threshold result is compared to the instantaneous graph result

and so its behaviour is different between long-term and short-term peak-to-peak graph selections.

c) G.8262 specifies a pp jitter measurement time of 60s. The global default capture configuration in

the Paragon-X is “manual” (indefinite). Selecting Sync-E jitter measurement under operating

mode forces the configure capture timing control to timed mode, 60s. Select other periods or

“manual” if required, eg for experimentation and observing long-term device behaviour. However,

60s must be selected for making a G.8262 compliance measurement.


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d) Initiate jitter measurement using the start capture key. This automatically displays the statistics

window, jitter measurement tab. This tab shows long-term (ie over the total elapsed time) pp and

RMS jitter results. It also shows the measurement bandwidth, which is fixed depending on

interface type selected. Limit checking is not applied to the jitter measurement tab. The tab can

be closed, and re-opened any time via the Statistics and Results key.

e) The main capture screen shows table entries updated once per second for long-term pp, long-

term RMS and short-term (one second) pp jitter results.

On the graph, use Graph Display Mode to select a result for graphing. The measurement

bandwidth is also displayed alongside the Y-axis legend on the graph.

Note that sample periods (1-second intervals) are numbered based on the start time of each one-

second period (ie, starting from 0), so for example a 60-second total measuring period will show

as containing sample periods 0-59.

Compare the 60s long-term peak-to-peak value to the G.8262 0.5UI limit.


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8. Wander (Noise) Tolerance – G.8262 Section 9


EEC Option 1

MTIE Wander

Table 7/Figure 5

TDEV Wander

Table 8/Figure 6

Sinusoidal Wander

Table 9/Figure 7

The EEC is;

i. Maintaining the clock within performance limits.

ii. Not causing any alarms.

iii. Not causing the clock to switch reference.

iv. Not causing the clock to go into holdover.

To Check whether the

EEC is switching

references or going

into holdover, the

Paragon can measure

the wander and/or

ESMC QL of the EEC

output.

EEC Option 2

TDEV Wander

Table 10/Figure 8

The EEC is;.

i. Maintaining the clock within performance limits

ii. Not causing any alarms.

iii. Not causing the clock to switch reference.

iv. Not causing the clock to go into holdover.


EEC is switching

references or going

into holdover, the

Paragon can measure

the wander and/or

ESMC QL of the EEC

output.

Measurement Setup


b) Set up the Paragon-X as described in section 3, including setting up ESMC with QL=PRC if using

ESMC to monitor if the EEC is switching clock references or going into holdover.


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Measurement Process

a) Select the “Wander and Jitter Generation” button on the Paragon-X GUI.

b) The Following window will now be open.

c) Select the Wander Tolerance Tab and the following window will open


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d) There are three methods of generating wander into the EEC:

i. MTIE/TDEV Wander – Fastest and most effective way to evaluate EEC

ii. Table Sinusoidal Wander – Can be used for finding Maximum Tolerable Wander

iii. Single Sinusoidal Wander – Can be used for troubleshooting

e) MTIE/TDEV Wander

The Paragon-X generates MTIE and TDEV wander as defined in G.8262.

i. Select the wander mask required from the drop down list. The mask and the maximum

running time will be shown on the right hand side of the window.

G.8262 Option 1 MTIE - Running Time is 1000s

G.8262 Option 1 TDEV - Running Time is 12000s

G.8262 Option 2 TDEV - Running Time is 12000s

ii. Click “Generate Wander” to start the test. The elapsed time will be displayed on the

bottom right hand side of the window.

iii. The test will stop after the max running time has elapsed, the test can also be stopped

manually by clicking “Stop Wander”.

f) Table (Sinusoidal)

Can be used to test Maximum Tolerable Wander


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The user can enter up to 10 different wander parameter sets in the table. The Paragon-X will

then automatically add each of the specified wander sets in turn giving full indication of progress

in the “Status” column. Switching between the different sets is always done at a zero crossing to

prevent phase steps.

i. Enter the frequency, amplitude, and dwell time (number of cycles the

frequency/amplitude pair will be run) for each wander test point.

The same frequency with different amplitudes can be entered to find maximum

tolerable wander

The Restore Defaults button when checked will restore the values to that defined

in table 9 in G.8262.

Only rows that have the “enable” check box ticked will be executed in the test. To

skip over a selection, un-tick the enable box for that selection.

ii. Click “Generate Wander” to start the test

iii. Click “Stop Wander” to stop the test. The test will terminate at the next zero crossing

iv. A pop up box stating how long to the next zero crossing is displayed, click the “Stop

Immediate” button if it is desired to stop the test instantly.

g) Single Sinusoidal Wander

Can be used for troubleshooting issues at a specific frequency


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i. Enter the frequency and amplitude of the desired wander

ii. Click “Generate Wander” to start the test

iii. Click “Stop Wander” to stop the test. The test will terminate at the next zero crossing of the

wander frequency

A pop up box stating how long to the next zero crossing is displayed.

h) G.8262 states that with the wander applied that the EEC should

i. Maintain the clock within the prescribed performance limits (the exact performance limits

are for further study)

ii. Not cause any alarms

iii. Not cause the clock to switch references

iv. Not cause the clock to go into holdover

For further insight, use the Paragon-X ESMC generation/capture capability and TIE graph

to check whether the EEC is switching clock reference or going into holdover.

i) Ensure the Paragon-X has been set up to Generate ESMC messages with QL=PRC as

described in section 3 of this document.

j) Select the “Start Capture” button to start the measurement.

k) To show both the TIE and ESMC graph at the same time click and then “Show 2nd

Graph” and then select “ON”

l) To change what a graph is displaying,

i. click one of the graphs (the selected graph will be non-Grey

ii. Click and then “Graph Display Mode”, finally select the graph to display


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Time Interval Error (TIE) vs Nominal

ESMC Rx Quality vs Time: (Port 1 Rx)

The screenshot above shows an EEC that has switched references or gone into holdover (top

graph is ESMC, bottom graph shows the difference in Frequency between the reference and the

recovered clock from the EEC)

m) To stop the measurement, select “Stop Capture”.


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9. Jitter Tolerance – G.8262 Section 9.2


EEC Option 1

and option 2

Test packet stream

from Paragon-X or

thru-mode traffic

Superimpose jitter to

G.8262 9.2 fig 9

The EEC does not drop

packets for all jitter

values presented

Either as pass/fail with

presented jitter values at

the mask, or a margin test

with jitter values above

mask.

Allow settling time at each

measurement point


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Measurement Setup a) Open Operating Mode dialog, change Operating Mode to Sync-E


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b) Open Setup Interface dialog

c) Select Tx+Rx Mode

d) Select 1GbE or 10GbE Line Rate


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e) Open Jitter dialog and select the Table tab


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f) From the TestPackets tab, the user configures the test packet they wish to generate.

g) From the Jitter Tolerance Table tab, the user enters the Frequency, Amplitude, and

Dwell Time for each row.

h) From the Jitter Tolerance Table tab, the user clicks the Start Test button. Test Packet

generation will be automatically controlled as each row in the Jitter table is executed.

i) The Jitter and Test Packet generation will automatically stop after all the enabled table

rows have been executed.

j) A PASS or FAIL result for each executed row will appear on the Jitter Tolerance Table

tab. The result will indicate if any Dropped packets were detected during the test.


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k) In the Max tolerable jitter mode, operation is similar except a percentage above or below

mask can be set for the generated jitter amplitudes.


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10. Wander (Noise) Transfer – G.8262 Section 10


EEC Option

1 Not defined

The phase gain of the EEC should be smaller than 0.2 dB (2.3%).

There is no definition of the

input stimulus to be used in

G.8262. Without further

guidance from the

Standards, it is suggested

that the amplitude and

frequency values associated

with mask points labelled f1,

f2 & f3 on G.8262 Section

9.1.1, Table 9 & Figure 7 are

used.

EEC Option

2

TDEV Wander

Table 10/Figure 8

Measure EEC output against TDEV Pass/Fail masks shown in G.8262 Section 10..2 Table 13/Figure 11

Measurement Setup

a) Connect the EEC to Paragon-X to EEC as shown in the diagram at the beginning of this

section


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b) Set up the Paragon-X as described in section 3, including setting up ESMC with QL=PRC if

using ESMC to monitor which clock the EEC is locked to.

Measurement Process

a) Select the “Wander and Jitter Generation” button on the Paragon-X GUI.

b) The Following window will now be open.

c) Select the Wander Transfer Tab and the following window will open


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G.8262 Option 1 Wander Transfer Test: Paragon-X automated testing

a) Select the “Table” tab.


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b) Enter the frequency, amplitude, and dwell time (number of cycles the frequency/amplitude pair

will be run) for each wander test point.

i. The Restore Defaults button when checked will restore the values to that defined in table 9 in

G.8262.

ii. Only rows that have the “enable” check box ticked will be executed in the test. To skip over a

selection, un-tick the enable box for that selection.

iii. Be careful to choose a dwell time of 300 cycles for any wander frequency of 1Hz or higher.

Additionally, choose the shortest sample period (configure capture button) available for

calibration and definitive measurement runs.

c) To calibrate the Paragon-X, connect a short Ethernet cable between Port 1 and Port 2 and click

the button.

d) When the calibration is finished the Status window will show


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e) Remove the short Ethernet cable between Port 1 and Port 2 and connect the EEC under test as

shown in the setup diagram at the start of this section.

f) Click the “Generate Wander” button to start the test.

g) The Paragon-X will show the status of the test, the measured Gain (dB) value and also a

Pass/Fail indication on the right hand side of the window.


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G.8262 Option 1 Wander Transfer Test: Paragon-X single frequency test

This capability can be used for fault finding issues at specific frequencies

a) Select the “Single” tab.

b) Enter the frequency and amplitude of the wander to be generated

c) To calibrate the Paragon-X, connect a short Ethernet cable between Port 1 and Port 2 and click

the button.

d) When the calibration is finished the Status window will show


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e) Remove the short Ethernet cable between Port 1 and Port 2 and replace with the EEC under test.

f) Click the “Generate Wander” button to start the test.

g) The GUI will show the estimated completion time at the bottom of the screen. The measured Gain

(dB) value and also a Pass/Fail indication (Green/Red background) will be displayed.


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G.8262 Option 2 Wander Transfer Test:

a) Select the “G.8262 Option 2” tab.

b) Press “Generate Wander” button to start the test.

c) The amount of the time until completion of the test is shown at the bottom right hand side of the

screen.

d) At any time during the test, it is possible to view an updated output TDEV graph by clicking the

“TDEV Results” button. The TDEV graph will then be displayed.


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e) At the end of the test the Paragon-X will automatically show the final MTIE graph and show

Pass/Fail against the MTIE mask.


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11. Phase Transient Response – G.8262 Section 11

11.1 G.8262 Section 11.1 Short-term phase transient response


EEC Option 1

EEC input reference is lost for 15 seconds and a 2nd reference input signal, traceable to the same reference clock, is available simultaneously

Maximum phase transient at the output due to reference switching to meet mask in G.8262 Figure 12

To emulate the loss of the

link either

Change ESMC

QL=DNU

Remove the cable

between port 2 and

EEC

EEC Option 2

EEC input reference

is lost for 15 seconds

and a 2nd reference

input signal, traceable

to the same reference

clock, is available

simultaneously

EEC output should meet MTIE mask defined by table 15/ Figure 14 in section 11.4.2 of G.8262


link either:

Change ESMC

QL=DNU

Remove the cable

between port 2 and

EEC

Measurement Setup



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b) Set up the Paragon-X as described in section 3 (including ESMC generation if using the ESMC

method of switching clock references, ensuring SSM code is set to PRC)

c) Select “Configure Capture” , select 10mSecs sample period and then close.

Measurement Process

a) There are two methods for determining Phase Transient Response with the Paragon-X;

i. Use ESMC Generation (if supported by the DUT).

ii. Remove the link between Port 2 on the paragon-X and the EEC input port.

b) Select the “Start Capture” button to start measurement.

c) If using the Ethernet cable removal method please disconnect cable between port 2 and the EEC.

d) If using ESMC method

i. Select button. The following window will open


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ii. Ensure SSM code is set to QL –PRC

iii. In the SSM Code drop down menu select QL – DNU/DUS and then click .

e) To stop the measurement click “Stop Capture”. .

Measuring Results

The switching transient will be seen on the Paragon-X TIE graph.

The Paragon-X graphs can show the TIE and also the ESMC QL for each port

In the screenshot bellow the ESMC graph shows the time and QL change of the ESMC transition

on Port 2 Tx of the Paragon-X. This can then be compared in time to the TIE graph showing the

Transient.

Method of evaluating the capture for phase transient response is dependent upon whether EEC

Option 1 or Option 2 is being evaluated.

EEC Option 1

a) To view the output TIE for EEC Option 1, closely monitor the output TIE graph on Paragon-X for

the duration (15s) of the test. While the slave clock is acquiring the new reference, the output

phase transient should be within the limits of figure 12 of G.8262 (provided below)


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EEC Option 2

a) To view the output MTIE mask for EEC Option 2 ONLY, perform the following:

b) To display the MTIE and TDEV graphs click on the bottom right hand side of the TIE

graph and then “MTIE/TDEV Analysis” from the displayed menu.

c) A separate window will open showing the TIE in graphical form at the top, with an MTIE/TDEV

graph at the bottom.


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d) The MTIE analysis can be carried out against the G.8262 masks for Wander Transient which

can be selected from the measurement mask pull down selection in the left hand window.

e) Pass/Fail indication against the masks is shown also in this left hand window and will have a

green background for “Mask Pass” and a red background for “Mask Fail”


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11.2 G.8262 Section 11.2 Long-term phase transient response

10.


EEC Option 1 EEC input reference is permanently lost or declared DNU

Maximum phase transient and excursion at the output due to reference switching to meet mask in G.8262 Figure 13


link either

Change ESMC

QL=DNU

Remove the cable

between port 2 and

EEC

Measure for 10,000

seconds (approx 3hrs)

EEC Option 2

EEC input reference

is permanently lost or

declared DNU

Maximum phase transient and excursion at the output due to reference switching to meet mask in G.8262 11.2.2 and table 14, including 1

st and 2

nd

derivatives of phase vs time


link either:

Change ESMC

QL=DNU

Remove the cable

between port 2 and

EEC

Measure for 10,000

seconds (approx 3hrs)

Measurement setup and process: EEC-1

Set the ESMC being generated on port 2 of the paragon to PRC. This will cause the DUT to lock to

this signal and hence to the Synchronisation Source.


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After allowing the DUT to settle, leave for at least 900s (15 minutes), measure the wander on Port 1.

The resulting graph should be flat and the Offset measurement at the foot of the Wander TIE graph

should indicate 0.000 ppm. The ESMC received from the DUT on Port 1 should also indicate PRC.

Restart the wander measurement and then set the ESMC on Port 2 to DNU (Do Not Use). This

should cause the the DUT to search for an alternative master clock signal to lock to. If there are no

other external signals then the DUT will use its internal clock. The ESMC messages on port 1 should

reflect this change with the appropriate Quality Level e.g. EEC1.

The TIE graph should show the SyncE signal from the DUT start to drift off. Leave the capture running

for a further 10,000 seconds (approx 3 hrs) minimum. Stop the measurement.

The limits of operation are given by this mask reproduced from G.8262 fig 13:

Check also that the TIE measurement shows a calculated frequency offset (shown at bottom of TIE

graph) within +/-4.6ppm.

For EEC-2, proceed as above, except the limit for TIE is as described in G.8262 11.2.2 and table 14,

illustrated here as a mask:


Reg. SC299625

The limits for EEC-2 1st derivative TIE (fractional frequency offset) and 2

nd derivative TIE (fractional

frequency drift) are also specified in table 14.

Currently it is not possible to compare results against the masks directly in Paragon-X, but two

methods of comparing results to G.8262 limits are available:

Method 1: direct observation of results from the Paragon-X (for EEC-1 and EEC-2 TIE), using marker

functions.

Method 2: export of Paragon-X TIE results as a .csv file, with subsequent processing in Excel. This

can be used for all cases, and is the only practical way to compute the 1st and 2

nd differentials of TIE in

the case of EEC-2.

On Paragon-X, after running the TIE measurement, use FILE, EXPORT to create a .csv file, then open

with Excel and perform the analysis.

Paragon-X exported TIE files show the TIE values as a single series of integers based on 1ns units.

To build a table of TIE versus time (S), compute the S values from the position in the series times the

sampling interval selected (default is 0.033 333 320 seconds, corresponding to 30 samples/s) and the

TIE values from the cumulative value of each series value minus 33333320. Compute derivatives

using the central difference approximation dTIE/dS = (TIE(n+1) - TIE(n-1))/0.066666640. The constants

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0 0 1 10 100 1000 10000 100000 1000000

TIE (nS)

Time S (seconds)

G.8262 11.2.2 EEC-2 TIE mask


Reg. SC299625

used in the calculation need to be changed to match the original capture sample rate, if it is varied

from its default 30/s.

See Calnex document CX5001e (on our website) as a practical example in Excel of the use of a

Paragon-x exported TIE file, with central difference differentiation examples.


Reg. SC299625

12. Appendix 1 - G.8262; Practical interpretation guidance

Frequency Accuracy – G.8262 Section 6


EEC Option 1

Free run +/- 4.6 ppm

Recommend to test

for an hour, longer if

close to limits

EEC Option 2

Hold over +/- 4.6 ppm

Recommend to test

for an hour, longer if

close to limits

Pull–in Range (G.8262 Section 7.1)


EEC

Option 1

and

EEC

Option 2

Apply a large Frequency

offset ensuring EEC is in

holdover. Reduce offset

until EEC locks.

EEC starts unlocked with large offset applied

EEC locks before offset reaches +/- 4.6ppm

Lock can also be

monitored by using

ESMC (if supported)

Hold–in Range (G.8262 Section 7.2)


EEC


EEC

Option 2




to +/-4.6ppm

EEC should remained locked at an offset at +/-4.6ppm

Lock can also be

monitored by using

ESMC (if supported)


Reg. SC299625

Pull–out Range (G.8262 Section 7.3)


EEC

Option 1




until the EEC unlocks.

EEC should remain locked at an offset at +/-4.6ppm but lock should extend beyond this.

G.8262 states this is for

further study

EEC


Wander Generation (G.8262 Section 8)


EEC Option 1

(Constant Temp)

- Locked Mode






EEC Option 1

(Temp effects)

- Locked Mode


- Temperature effects

MTIE Pass/Fail masks shown in G.8262 Section 8.1.2.


TDEV – G.8262 states

for further study

EEC Option 2

(Constant Temp)

- Locked Mode







Reg. SC299625

Wander Tolerance (G.8262 Section 9)


EEC Option 1

MTIE Wander

Table 7/Figure 5

TDEV Wander

Table 8/Figure 6

Sinusoidal Wander

Table 9/Figure 7

The EEC is;

v. Maintaining the clock within performance limits.

vi. Not causing any alarms.

vii. Not causing the clock to switch reference.

viii. Not causing the clock to go into holdover.


EEC is switching

references or going

into holdover, the

Paragon can measure

the wander and/or

ESMC QL of the EEC

output.

EEC Option 2

TDEV Wander

Table 10/Figure 8

The EEC is;.

v. Maintaining the clock within performance limits

vi. Not causing any alarms.

vii. Not causing the clock to switch reference.

viii. Not causing the clock to go into holdover.


EEC is switching

references or going

into holdover, the

Paragon can measure

the wander and/or

ESMC QL of the EEC

output.

Wander Transfer (G.8262 Section 10)


EEC Option 1 Not defined The phase gain of the EEC should be smaller than 0.2 dB (2.3%).

There is no definition of the

input stimulus to be used in

G.8262. Without further

guidance from the Standards,

it is suggested that the

amplitude and frequency

values associated with mask

points labelled f1, f2 & f3 on

G.8262 Section 9.1.1, Table 9

& Figure 7 are used.

EEC Option 2

TDEV Wander

Table 10/Figure 8

Measure EEC output against TDEV Pass/Fail masks shown in G.8262 Section 10..2 Table 13/Figure 11


Reg. SC299625

Transient Response (G.8262 Section 11)


EEC Option 1

EEC input reference is lost for 15 seconds and a 2nd reference input signal, traceable to the same reference clock, is available simultaneously

Maximum phase transient at the output due to reference switching to meet mask in G.8262 Figure 12


link either

Change ESMC

QL=DNU

Remove the cable

between port 2 and

EEC

EEC Option 2

EEC input reference

is lost for 15 seconds

and a 2nd reference

input signal, traceable

to the same reference

clock, is available

simultaneously

EEC output should meet MTIE mask defined by table 15/ Figure 14 in section 11.4.2 of G.8262


link either:

Change ESMC

QL=DNU

Remove the cable

between port 2 and

EEC

For more information on the Calnex Paragon-X and to take advantage of Calnex’s extensive experience in

sync and packet testing technologies, please contact Calnex Solutions on +44 (0) 1506 671 416 or email:

[email protected]

Calnex Solutions Ltd Herkimer House Mill Road Enterprise Park Linlithgow West Lothian EH49 7SF United Kingdom Tel: +44 (0) 1506 671 416 Email: [email protected]

www.calnexsol.com

CX5001 v11 Jan 2013

This information is subject to change without notice

© Calnex Solutions Ltd, 2010

Documents

G.8262 SyncE Conformance Testing