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Telecommunications Industry Association TR41.9-16-02-XXX Document Cover Sheet Project Number TIA-PN-31-D-4 Document Title Signal Power Limitations test procedures for FAST DSL Source Cisco Systems Contact Tim Lawler 170 West Tasman Dr. San Jose, CA 95134 Distribution TR-41.9 Intended Purpose of Document (Select one) X Phone: (408) 527-0681 Fax: (408) 853-3288 Email: [email protected] For Incorporation Into TIA Publication For Information Other (describe) - The document to which this cover statement is attached is submitted to a Formulating Group or sub-element thereof of the Telecommunications Industry Association (TIA) in accordance with the provisions of Sections 3.3.2.2 through 3.3.2.4 inclusive of the TIA Engineering Committee Operating Procedures dated May 2014, all of which provisions are hereby incorporated by reference. Abstract This contribution is a proposal for adding Signal Power Limitations test procedures for FAST DSL to TSB31-D-4. V2.1 – 20141205 Telecommunications Industry Association TR41.9-16-02-XXX Add the following items to sub-clause 5.5, Suggested Equipment List (SEL): (80) RF power meter: minimum sensitivity of 0.1 V and a minimum input impedance of 10 kohm over the frequency range from 1 MHz to 300 MHz minimum. (81) Spectrum analyzer: input impedance 50 ohms, frequency range from 30 MHz to at least 300 MHz, sensitivity of -130 dBm/Hz or better, resolution < 1 Hz, absolute amplitude accuracy +1.5 dB or better. (82) 100:50 ohm balun transformer: frequency range 30 MHz to 300 MHz minimum. Page 2 Telecommunications Industry Association 9.41 556B TR41.9-16-02-XXX Signal Power Limitations, FAST Terminal Equipment TIA-968-B-3, 5.3.10.1 9.41.1 Background The aggregate signal or total power of the FAST modem must be limited to minimize near end crosstalk (NEXT) with other DSL systems that share the same cable binder. Crosstalk is widely recognized as a form of third party harm and represents the principal impairment to many DSL systems. 557B 9.41.2 Purpose The purpose of this test is to verify that the signal power level transmitted to the network does not exceed the requirement. 558B 9.41.3 Equipment (1) RF power meter SEL#80. (2) 100 ohm, 1 %, non-inductive resistor. Note: Refer to subclause 5.5 for equipment details. 559B 9.41.4 Equipment States Subject to Test The equipment under test should be transmitting continuously at its highest obtainable signal power. 560B 9.41.5 Procedure (1) Condition the EUT to transmit its upstream signals at the highest power level. (2) Connect the EUT to the test circuit of Figure 9.41-1. (3) Measure and record the signal power level in dBm. The level should be averaged over a time span of at least 10 seconds or longer if short term variations are observed. 561B 9.41.6 Alternative Method The total signal power may also be calculated by integrating the PSD over the operating band. This task consists of measuring the PSD over the operating band using a 10 kHz resolution bandwidth at discrete frequencies with a stepped interval of 10 kHz. The individual PSD readings are then converted to power readings by multiplying the PSD (in terms of watts/Hz) by the 10 kHz resolution bandwidth. This results in a power level for each 10 kHz window. These are then summed over the operating band to give the total power. Page 3 Telecommunications Industry Association 562B 9.41.7 TR41.9-16-02-XXX Suggested Test Data (1) Signal power level. (2) Loop characteristics or test mode via software used to obtain the total power measurement. 563B 9.41.8 Comments (1) If the RF power meter has a 50 ohm input impedance then a 50 to 100 ohm BALUN may be necessary. (2) Care must be taken to ensure that measurement errors are kept to a minimum. Sources of error may include the following: Impedance deviations from the ideal 100 ohm termination BALUN loss (if used) FIGURE 9.41-1 AVERAGE SIGNAL POWER Note: If the RF power meter has 50 ohms input impedance, a 50 to 100 ohm BALUN is needed and the 100 ohm resistor would be removed. Page 4