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    Fiber optic transmission

     One of the many advantage of using optical fiber over copper cable for transmitting signals over long distances is the much lower levels of loss involved. this means that fewer repeaters are required which provides for enormous cost and energy saving. read more...         

        To perform the Experiment please follow the procedure: 

1.  Install the run time engine program to operate each VI. 

2.  Activate the functions generator and scope by pressing the  from the tool bar, and then press the  in each.

3. Adjust the function generator using its soft controls for an output with the following specifications:

Wave Form Shape



1 Hz


5 Vp-p

DC offset

0 V

4. Select one of the red LED transmitter modules and set its Mode control at ANALOG.


5. Turn the receiver module's Variable Gain control fully counter-clockwise.


6. Launch and run the NI ELVIS II Oscilloscope VI. and Set the values for the scope as follows:



Channel 0

Channel 1


2 V

2 V

DC offset

0 V

0 V


200 µ sec 200 µ sec


7.  Activate the scope's channel 1 input (by checking the channel 1 enabled box) to observe the Receiver module's output as well as the original message.


8. Increase the message frequency (that is, increase the function generator's output frequency) to the following setting: 10hz 20hz 50hz and 1000hz, and take a screen shoot for each.



9. Increase the message's amplitude (that is, the function generator's output voltage) in 1V increments up to 10vpp and observe the effect, and take a screen shoot for each.


10. What is the name if the distortion that appears on the Receiver module's output.


11. What causes the distortion on the lower peaks of the waveform?


12. What causes the distortion on the upper peaks of the waveform?


13. Would you expect the green transmitter module to perform differently to the red Transmitter module in the tests you've made so far in part b? explain your answer.