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Programming Documents for Pre-K for SA - The City of San Antonio

Programming Documents for Pre-K for SA - The City of San Antonio

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3) Measuring link attenuation (each link)<br />

4) Calculating link attenuation (each link)<br />

A.3.3.3 Setting the reference<br />

When referencing the light source to the power meter, one test jumper (J1) is to be connected between<br />

the light source and the power meter and a reference measurement taken (P1[dBm]).<br />

NOTE – To improve the stability <strong>of</strong> the reference reading and <strong>for</strong> easier handling, it may be helpful to<br />

secure the mandrel to the light source by some means such as a cable tie or tape. Care should be taken<br />

to ensure that the fiber jacket is not de<strong>for</strong>med or damaged when using a cable tie or tape.<br />

A.3.3.4 Measuring link attenuation<br />

Connect the end <strong>of</strong> test jumper (J1) (source end) to one end <strong>of</strong> the link, and connect an acceptable test<br />

jumper (J2) between the other end <strong>of</strong> the link and the meter (see Figure 28 on next page). <strong>The</strong> optical<br />

power reading is P2 (dBm).<br />

A.3.3.5 Calculating link attenuation<br />

Equation 1 is used to determine the fiber cabling link loss (attenuation).<br />

where:<br />

P1 = Reference power measurement<br />

P2 = Cabling test power measurement<br />

84

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