ANSI SCTE 109-2019 pdf free download – Test Procedure for Common Path Distortion (CPD).
Reliable operation of today’s two-way cable networks is critical, especially considering that upstreamtransmission in the return path includes telephone, high-speed data,and various telemetry and othersignals. Common path distortion(CPD)is a type of impairment that can affect the quality of those
upstream signals. This document describes test procedures for the characterization of CPD in lab and fieldcnvironments.
1.2. Scope
The purpose of this document is to establish the standard methodology used to measure CPD in both a laband in a live cable network.
The lab procedure is a very unique procedure for measuring common path distortion and distinguishesitself from other similar procedures in the following ways:
.Single port measurement, measures reflected energy
.Inject two forward carriers separated by 6 MHz and measure return beat at 6 MHz
Used to verify performance of single port passives such as terminators or passives with allother ports terminated. Designed to be consistent with the mechanisms that cause commonpath distortion in outside plant.
A procedure also is included to adapt and extend the lab test method to a live cable network, involving theinjection of downstream carriers at certain frequencies in the headend or hub, and measuring an upstreambeat (or beats) at a headend/hub upstream test point.
The examples in this document focus on a 5 MHz to 42 MHz upstream spectrum, although other
upstream bandwidths can be used (e.g., 5 MHz to 85 MHz). The methods described in this document canbe adapted to any choice of upstream spectrum bandwidths without materially impacting the results.
1.3. Benefits
This document describes standard methodology that can be used for characterizing CPD in a lab and fieldenvironment. In particular, the lab method is unique in that it supports CPD characterization of single-portdevices.An extension of the lab method intended for use in a live cable network can be thought of as
treating the entire network as a single-port “black box” of sorts. The procedures in this document canaugment other CPD test and measurement techniques used by the cable industry.
1.4. Intended Audience
The intended audience for this document includes technicians, engineers, and others with an interest inmeasuring CPD in a lab environment and/or in a live cable network.
1.5. Areas for Further lnvestigation or to be Added in Future Versions
One suggested area for further investigation is follow-up field evaluation of the method described inSection 9.3 Live Plant Third Order CPD Test.
2. Normative References
The following documents contain provisions,which, through reference in this text, constitute provisionsof this document.At the time of Subcommittee approval, the editions indicated were valid.All documentsare subject to revision; and while parties to any agreement based on this document are encouraged to
investigate the possibility of applying the most recent editions of the documents listed below, they arereminded that newer editions of those documents might not be compatible with the referenced version.
2.1.SCTE References
ANSI/SCTE 144 2017:Test Procedure for Measuring Transmission and Reflection2.2. Standards from Other Organizations
. No normative references are applicable.
2.3. Published Materials
.No normative references are applicable.3. Informative References
The following documents might provide valuable information to the reader but are not required whencomplying with this document.
Each of these procedures targets a different measurement for a unique purpose.They are independent, arespecifically applicable to the device being measured, use the test equipment commonly available at themanufacturing sites used to make the device being tested, and directly measure the impairment that mustbe controlled.The key differences are whether they are designed for actives or passives and whether theyare single port or two port measurements. Other differences are the types of distortion products beingmeasured and the filters required to do so.
3.1.SCTE References
ANSI/SCTE 115 2019:Test Method for Reverse Path (Upstream) Intermodulation Using Two
Carriers
ANSISCTE 126 2019: Test Method for Distortion of 2-way Active Amplifier Caused byInsufficient Isolation of Built in Diplex Filter
ANSI/SCTE 145 2015: Test Method for Second Harmonic Distortion of Passives Using a SingleCarrier
3.2. Standards from Other OrganizationsNo informative references are applicable.
3.3. Published Materials
Williams,T.,Rupc,J. , “Common Path Distortion(CPD) in Digital Cable Networks.”
SCTE·ISBEJournal of Network Operations， Volume 4, Number 1 December 2018.ANSI SCTE 109 pdf download.