ANSI SCTE 109 pdf free download
ANSI SCTE 109 pdf free download.Test Procedure for Common Path Distortion (CPD).
2. Normative References
The following documents contain provisions, which, through reference in this text, constitute provisions of this document. At the time of Subcommittee approval, the editions indicated were valid. All documents are 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 arc reminded 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 Reflection
2.2. 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 when complying with this document.
Each of these procedures targets a different measurement for a unique purpose. They are independent, arc specifically applicable to the device being measured, use the test equipment commonly available at the manufacturing sites used to make the device being tested, and directly measure the impairment that must be controlled. The key differences arc whether they are designed for actives or passives and whether they are single port or two port measurements. Other differences are the types of distortion products being measured 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
• ANSI/SCTE 126 2019: Test Method for Distortion of 2-way Active Amplifier Caused by Insufficient Isolation of Built in Diplex Filter
• ANSI/SCTE 145 2015: Test Method for Second Harmonic Distortion of Passives Using a Single Carrier
3.2. Standards from Other Organizations
• No informative references are applicable.
3.3. Published Materials
• Williams. T., Rupe, J., “Common Path Distortion (CPD) in Digital Cable Networks.” SCTE ISBE Journal of Network Operatiotis, Volume 4, Number 1 December 2018
• Williams. T., Hamzeh B., Hranac, R., “Field Measurements of Nonlinear Distortion in Digital Cable Plants.” 2014 NCTA Technical Papers
• Large, D., Farmer, J., Broadband Cable Access Networks. © 2009 Morgan Kaufmann Publishers
• Ciciora, W., Farmer J., Large D., Adams, M., Modern Cable Television Technology, 2” Ed. © 2004. Morgan Kaufmann Publishers
• Raskin, D., Stoneback, D., Broadband RL’lurll Systems for Hybrid Fiher/oax cable TV Networks. © 1998, Prentice Hall PTR
• Patel, B. “Report on Common Path Distortions.” February 1998
• Reichert. Jr., H., “CATV System Return Path Interference.” 1982 NCTA Technical Papers
6. CPD Overview
Common path distortion is a well-known impairment that affects a cable network’s return path. CPD comprises nonlinear distortions other than those generated in active devices, and which appear in the upstream spectrum. While CPD can include higher order distortions, second and third order distortions are generally the most prevalent. In operating cable networks, CPD is usually in the class of composite distortions, similar to composite second order (CSO) and composite triple beat (CTB) distortions generated in active devices.
CPD occurs when downstream RF signals pass through a diode-like nonlinearity, typically at interfaces where corrosion has formed in the signal path common to the downstream and upstream spectrums. The resulting oxide layer behaves somewhat like a semiconductor, and can be just a few molecules thick, making it fragile and susceptible to being affected by wind, vibration, temperature changes, and so on. All of the aforementioned, in addition to varying downstream RF signal levels, complicate location and troubleshooting of CPD sources.
Some of the (‘PD generated by the diode-like nonlinearity occurs in the downstream and some in the upstream. The downstream CPD appears on the same frequencies as existing downstream composite distortions ((‘SO and CTB) and cannot be easily differentiated from (‘SO and CTB produced by active devices.’ What is of concern in this document is the distortions that appear in the upstream spectrum, which propagate toward the node and headend/hub. When the cause of the CPD is identified and repaired, the (‘PD that was occurring in both directions will be eliminated.ANSI SCTE 109 pdf download.
