Canoga-perkins 9145ELB Network Interface Device Hardware Manuel d'utilisateur télécharger pdf (Page 47)

Maintenance 9145ELB NID Hardware User’s Manual

Checking Optical Power Levels

web site. The power level must be lower than the saturation level. If not, contact Canoga

Perkins Technical Support.

Figure 6-2 Measuring Receiver Input Power

6.2.3 Calculating Fiber Link Attenuation

Link attenuation measurement identifies potential problems with links that are on the threshold of

receiver sensitivity. Measure optical fiber links at the shortest wavelength of operation, as it is the

limiting factor in the loss budget. Use a power meter calibrated for the laser source, then factor in

approximately 1 dB for the connector loss from the patch cables between the 9145ELB and the

local device. (Each fiber connection can generate 0.5 dB of additional loss.)

If you cannot determine the Rx sensitivity, contact Canoga Perkins Technical Support for

assistance.

Follow these steps to calculate fiber link attenuation:

1. Determine transmitter output power as described in section 6.2.1.

2. Determine receiver input power as described in section 6.2.2.

3. Subtract receiver input power from transmitter output power. The result is the fiber link

attenuation.

Transmit Output Power -7.0 dBm

Receiver Sensitivity -28.2 dBm

Fiber Link Attenuation 21.2 dB

FIBER OPTIC

TRANSMITTER

FIBER OPTIC

RECEIVER

OPTICAL

POWER

METER

-24dBm

λ = 1300 nm

FIBER OPTIC

TRANSMITTER

FIBER OPTIC

RECEIVER

OPTICAL

POWER

METER

-24dBm

λ = 1300 nm

LOCAL SITE

REMOTE SITE

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Canoga-perkins 9145ELB Network Interface Device Hardware Manuel d'utilisateur Page 47