28Chapter 2 Calculating transmission distance
How to calculate expected loss budget
To calculate the expected loss budget for a proposed network configuration:
1Identify all points where signal strength will be lost.
2Calculate the expected loss for each point.
3Add the expected losses together.
How to calculate maximum transmission distance
The examples in this chapter use the following assumptions and procedure for calculating the maximum transmission distances for networks with CWDM GBICs, CWDM OADMs, and CWDM OMUXs.
Assumptions
The examples assume use of the values and information listed in Table 2.
Table 2 Assumptions used in calculating maximum transmission distance
Item | Assumption |
|
|
Cable | Single mode fiber optic cable (SMF) |
|
|
Repair margin | 01 |
Maximum link budget | 30 dB2 |
|
|
System margin | 3 dB (allowance for misc. network loss) |
|
|
Fiber attenuation | .25 dB per kilometer |
|
|
Operating temperature | 0 - 40°C (32 - 104°F) |
|
|
CWDM OADM expected loss3 | Use of “CWDM OADM specifications” on page 45 |
|
|
CWDM OMUX expected loss3 | Use of “CWDM OMUX specifications” on page 47 |
|
|
1Use your organization’s expected repair margin for percentage of the total fiber plant loss for each
2From specifications in Installing CWDM Gigabit Interface Converters, part number
3Multiplexer loss values include connector loss.
