Digital communications

# Learning outcomes

After studying this course, you should be able to:

- convert between wavelengths and frequencies
- describe the main differences between lasers and LEDs as used as light sources for optical-fibre communications systems
- describe the difference between direct and external modulation of a laser
- describe the difference in structure and performance of step-index multimode, graded-index multimode and single-mode optical fibres
- draw up a power budget for an optical-fibre communication link and use it to estimate the maximum link distance.

OpenLearn - Digital communications
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