Any electrical engineers?!

Discussion in 'Off-Topic Chat' started by wewizrobbed, Jan 16, 2008.

  1. wewizrobbed

    wewizrobbed Member

    Hopefully some of you are engineers! Can someone please help me with this question:

    If the following system is operated at its attenuation limited link length, can it be used to transmit at a bit rate of 1Gbit/sec?

    Transmitter: 1300nm laser with a 0.8nm linewidth and launching 4mW into the fibre.

    Fibre: 1300nm single node fibre with a dispertion coefficient of 3ps/km.nm and an attenuation coefficient of 0.32dB/km.

    Receiver: InGaAsP PinFET with a sensitivity of -26dBm and a max tolerable pulse spread of 0.2T (T=bit period).

    Joint losses, system margin and power penalties = -9dB

    I've worked out the power budget, which is OK but I don't know how to do the bit rate analysis completely. I've worked out that the actual pulse spread is 172.5ps but I don't know what to do to calculate the bit period and maximum pulse spread. My notes aren't very clear and my exam is tomorrow haha!

    If anybody has any idea please let me know!!

    Luce x
  2. stevetrom

    stevetrom Well-Known Member

    As an electrical engineer of 20+ years experience my advide would be to switch it on and see if it works !

    Sorry, not my field of expertise (in other words I don't have a clue)
  3. rutty

    rutty Active Member

    This is right in the area of expertise that I should have but I'm afraid I have no idea what the answer might be ;)

    You sound like you might be doing a course I may benefit from. What are you taking?
  4. wewizrobbed

    wewizrobbed Member

    It's ok, I've got it now!! :D

    I'm doing a degree in Electrical and Mechanical engineering, this is from my photonics class, which I'm about to fail in an hours time. Treat!