# OTDR- How to intrepret the digital values of OTDR that are in digits.

• posted

Dear group members, I have a problem, hope you all would help me in stating how to solve this issue. My professor gave me a task in Optical communcation course where I hav to interpret the OTDR - values, that have been generated for CRO and give the following in results. 1. What is the Initial Pulse? 2. What is the attenuation for the fiber 1 and fiber 2 3. what is the connector loss?

Now the problem i have is the values given to me is in the form of volts, i.e for the y axis. I know the formula to find the distance for the x axis is Distance = 3 * 10 E8 ( T ) / (2 * n)

where T = time and the n is the refractive index. The reason dividing by 2, coz of backscattering.

Where Refractive index is given as n = 1.475

First of all iam having problem how to interpret with the given datas which is given below. Can any one help me to sort this out since my other professors were in holidays and the day they were coming is the day I hav to submit. The details were given below.

Thanks, Mukundan

Given:

Type: normal Points: 512 Count: 1 XInc: 3.99999997569E-08 XOrg: -1.98650000151254E-06 XRef: 6 YData range: 6.50789E+00 YData center: 2.10445E+00 Coupling: DC XRange: 2.00000E-05 XOffset: -2.00000000000000E-06 YRange: 6.50789E+00 YOffset: 2.10445E+00 Date: 21 JUN 1967 Time: 85:04:47 Frame: 54542A:0000A00000 Acq mode: real time Completion: 100 X Units: second Y Units: Volt Max Bandwidth: 500000000 Min Bandwidth: 0 Data: 5.96E-02 4.69E-02 4.21E-02 3.42E-02

4.85E-02 6.76E-02 8.03E-02 8.98E-02 8.03E-02 6.76E-02 4.85E-02 3.42E-02 3.58E-02 3.42E-02 4.69E-02 5.33E-02 5.96E-02 6.60E-02 5.96E-02 5.33E-02 4.69E-02 3.42E-02 3.58E-02 3.42E-02 6.28E-02 8.98E-02 8.03E-02 8.03E-02 8.03E-02 8.98E-02 8.66E-02 8.50E-02 9.93E-02 8.50E-02 8.66E-02 8.98E-02 7.39E-02 6.12E-02 5.33E-02 6.12E-02 8.03E-02 1.06E-01 1.18E-01 1.34E-01 1.03E-01 1.01E-01 9.62E-02 8.82E-02 7.39E-02 6.76E-02 5.17E-02 8.98E-02 5.17E-02 6.12E-02 1.03E-01 8.19E-02 2.88E+00 4.28E+00 4.40E+00 4.44E+00 4.36E+00 2.48E+00 2.41E+00 2.34E+00 2.30E+00 2.27E+00 2.26E+00 2.25E+00 2.24E+00 2.23E+00 2.23E+00 2.23E+00 2.23E+00 2.23E+00 2.22E+00 2.22E+00 2.22E+00 2.22E+00 2.22E+00 2.22E+00 2.21E+00 2.20E+00 2.19E+00 2.18E+00 2.18E+00 2.18E+00 2.18E+00 2.18E+00 2.17E+00 2.16E+00 2.15E+00 2.15E+00 2.15E+00 2.15E+00 2.15E+00 2.15E+00 2.15E+00 2.14E+00 2.14E+00 2.14E+00 2.15E+00 2.15E+00 2.15E+00 2.14E+00 2.14E+00 2.13E+00 2.13E+00 2.13E+00 2.14E+00 2.13E+00 2.13E+00 2.13E+00 2.13E+00 2.12E+00 2.12E+00 2.12E+00 2.11E+00 2.10E+00 2.10E+00 2.09E+00 2.09E+00 2.09E+00 2.09E+00 2.08E+00 2.08E+00 2.07E+00 2.06E+00 2.06E+00 2.06E+00 2.06E+00 2.06E+00 2.06E+00 2.06E+00 2.05E+00 2.05E+00 2.07E+00 2.10E+00 4.18E+00 4.31E+00 4.28E+00 3.12E+00 2.58E+00 2.29E+00 2.13E+00 2.03E+00 1.96E+00 1.91E+00 1.88E+00 1.86E+00 1.85E+00 1.84E+00 1.85E+00 1.86E+00 1.85E+00 1.84E+00 1.83E+00 1.83E+00 1.82E+00 1.82E+00 1.81E+00 1.80E+00 1.79E+00 1.79E+00 1.79E+00 1.79E+00 1.79E+00 1.79E+00 1.78E+00 1.78E+00 1.78E+00 1.78E+00 1.77E+00 1.77E+00 1.77E+00 1.77E+00 1.77E+00 1.76E+00 1.74E+00 1.74E+00 1.74E+00 1.75E+00 1.75E+00 1.75E+00 1.75E+00 1.75E+00 1.74E+00 1.74E+00 1.74E+00 1.74E+00 1.74E+00 1.73E+00 1.72E+00 1.71E+00 1.71E+00 1.71E+00 1.71E+00 1.71E+00 1.70E+00 1.70E+00 1.70E+00 1.71E+00 1.71E+00 1.71E+00 1.70E+00 1.69E+00 1.68E+00 1.67E+00 1.66E+00 1.65E+00 1.65E+00 1.65E+00 1.65E+00 1.65E+00 1.65E+00 1.65E+00 1.67E+00 1.69E+00 3.81E+00 4.26E+00 4.23E+00 3.96E+00 2.94E+00 2.44E+00 2.07E+00 1.84E+00 1.61E+00 1.42E+00 1.26E+00 1.11E+00 9.91E-01 8.65E-01 8.27E-01 7.73E-01 7.32E-01 6.84E-01 6.78E-01 6.84E-01 6.40E-01 6.43E-01 6.36E-01 6.27E-01 6.17E-01 6.17E-01 6.17E-01 6.33E-01 6.17E-01 6.17E-01 6.17E-01 6.27E-01 6.36E-01 6.36E-01 6.30E-01 6.33E-01 5.95E-01 5.97E-01 5.93E-01 6.00E-01 6.00E-01 6.00E-01 5.93E-01 5.89E-01 5.89E-01 5.89E-01 5.89E-01 5.89E-01 5.82E-01 5.78E-01 5.78E-01 5.73E-01 5.68E-01 5.68E-01 5.68E-01 5.68E-01 5.68E-01 5.63E-01 5.60E-01 5.60E-01 5.60E-01 5.60E-01 5.60E-01 5.60E-01 5.52E-01 5.46E-01 5.39E-01 5.33E-01 5.33E-01 5.33E-01 5.33E-01 5.33E-01 5.33E-01 5.33E-01 5.33E-01 5.33E-01 5.33E-01 5.33E-01 5.43E-01 5.76E-01 1.71E+00 2.75E+00 2.94E+00 2.75E+00 2.44E+00 2.16E+00 1.87E+00 1.63E+00 1.41E+00 1.20E+00 1.01E+00 8.17E-01 7.44E-01 6.57E-01 5.87E-01 5.22E-01 4.43E-01 4.23E-01 3.89E-01 3.61E-01 3.42E-01 3.30E-01 3.19E-01 3.15E-01 2.90E-01 2.76E-01 2.68E-01 2.68E-01 2.61E-01 2.55E-01 2.36E-01 2.55E-01 2.61E-01 2.68E-01 2.68E-01 2.68E-01 2.68E-01 2.61E-01 2.55E-01 2.44E-01 2.36E-01 2.03E-01 2.31E-01 2.50E-01 2.42E-01 2.36E-01 2.25E-01 2.18E-01 2.18E-01 2.18E-01 2.18E-01 2.18E-01 2.18E-01 2.18E-01 2.18E-01 2.18E-01 2.25E-01 2.31E-01 2.31E-01 2.31E-01 2.31E-01 2.36E-01 2.49E-01 2.55E-01 2.55E-01 2.49E-01 2.44E-01 2.44E-01 2.44E-01 2.49E-01 2.55E-01 2.55E-01 2.55E-01 2.49E-01 2.38E-01 2.31E-01 2.25E-01 2.18E-01 2.36E-01 2.52E-01 5.95E-01 1.64E+00 2.12E+00 2.21E+00 2.02E+00 1.79E+00 1.56E+00 1.34E+00 1.14E+00 9.62E-01 8.06E-01 6.74E-01 5.62E-01 4.70E-01 3.92E-01 3.25E-01 2.73E-01 2.26E-01 1.85E-01 1.68E-01 1.49E-01 1.37E-01 1.25E-01 1.20E-01 1.20E-01 1.20E-01 1.20E-01 1.14E-01 9.46E-02 7.55E-02 3.42E-02 5.48E-02 6.76E-02 8.66E-02 9.93E-02 1.07E-01 9.93E-02 8.66E-02 7.39E-02 7.23E-02 8.50E-02 9.93E-02 1.12E-01 1.20E-01 1.20E-01 1.20E-01 1.20E-01 1.14E-01 9.93E-02 9.30E-02 8.19E-02 9.93E-02 1.12E-01 1.14E-01 1.07E-01 1.01E-01 9.62E-02 1.01E-01 9.93E-02 9.30E-02 8.19E-02 9.30E-02 9.93E-02 1.14E-01 1.12E-01 9.93E-02 8.19E-02 9.30E-02 9.93E-02 1.07E-01 1.14E-01 1.03E-01 1.34E-01 1.25E-01 1.25E-01 1.20E-01 1.20E-01 1.14E-01 1.07E-01 1.03E-01 1.41E-01 2.52E-01 4.46E-01 5.60E-01 5.44E-01 5.25E-01 4.50E-01 3.66E-01 3.04E-01 2.50E-01 2.12E-01 1.80E-01 1.55E-01 1.37E-01 1.25E-01 1.20E-01 1.12E-01 9.30E-02 7.23E-02 5.17E-02 5.33E-02 5.33E-02 5.33E-02 5.33E-02 5.33E-02 5.96E-02 7.39E-02 8.03E-02 8.98E-02 8.66E-02 8.19E-02 9.30E-02 9.93E-02 1.07E-01 9.93E-02 9.30E-02 8.19E-02 8.66E-02 8.82E-02 9.62E-02 9.62E-02 1.01E-01 9.93E-02 9.30E-02 8.50E-02 7.23E-02 7.39E-02 8.66E-02 9.30E-02 9.30E-02 8.50E-02 6.60E-02 5.33E-02 5.33E-02 5.33E-02
• posted

Initial Pulse -

it is value in [dB/km] - peoperty of any cable. Connector loss - loss inserted thrue connector. For any type of connector (ST. SC, LC etc.) is different value.

• posted

I think, first of all u have to plot this data. The formula u have for X-axis is correct, where T would be equal to sample interval multiply by 10th data. By the way what is the resolution of this data. Good luck Imran

• posted

Dear Mukundan,

Are you still working on this problem? If yes, when is your "due date?" Would you still like some assistance in interpreting the data?

Regards,

Joe

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