Based on a recent meeting of the International Telecommunications Union (ITU) Study Group 4, Agilent Technologies Inc. said the Jitter Working Party has agreed in principle to the draft of ITU-T O.172 Appendix VII, "Method for Verification of Measurement Result Accuracy and Intrinsic Fixed Error." The methodology and content of O.172 Appendix VII was initiated and driven by Agilent, primarily from its facility in South Queensferry, Scotland, which is the design and production center for its OmniBER family of jitter measuring equipment. The September 2004 meeting was hosted in Palo Alto, Calif., and involved participants from jitter test equipment manufacturers and standards bodies.

O.172 Appendix VII provides a procedure for verifying receiver accuracy of jitter measuring equipment and requires the production of jitter "accuracy maps," which provide detailed indications of individual receiver accuracy performance. The draft will be submitted for ratification at the next ITU-T Study Group 4 meeting in early 2005.

"Since its inception, Recommendation O.172 has specified the measurement accuracy of jitter instruments but has not detailed how to verify this performance," said David Taylor, Agilent's representative (ITU "rapporteur") on the ITU-T Jitter Working Party. "The new O.172 Appendix VII will fill this gap and provide the basis for receiver-only performance calibration and specification, enhancing accuracy and box-to-box result consistency."

An O.172 Appendix VII-based accuracy enhancement is already standard on Agilent's OmniBER OTN jitter products and provides a receiver-only, fixed jitter accuracy specification of 15 mUI. In addition, O.172 Appendix VII accuracy maps (for both 2.5 and 10 Gb/s rates) are supplied with every new OmniBER OTN unit.

Another new O.172 proposal, Appendix VIII "Method for Characterization of Transmit Intrinsic Jitter," was also discussed at the meeting. This appendix serves as a diagnostic tool for the characterization of test equipment jitter transmitters under certain restricted conditions. Agilent advanced this draft appendix by proposing a new measurement algorithm, which was accepted. The Jitter Working Party also agreed in principle to this draft, which is being submitted for ratification at the early-2005 ITU-T Study Group 4 meeting.

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