TDM Bus efficiency

[ptwilson]

G'day, can anyone please help me or steer me in to the appropriate area please. I am trying to calculate the amount of bits that should be transmitted in a time slot to achieve an efficiency of 99% with the following info.
Velocity of Propagation is 0.8c
Bus Length is 10M
data Rate is 500Mb/s
Thank you. :?:

 

[panic mode]

Sounds like homework but let's see if I get it right...

500kbit/sec > 500*1024bit/sec > 512000bit/sec

If you can transfer 512000 bits in one second, single bit transfer rate
becomes 1sec/512000=0.000001953sec=1.953microsecond (usec).
This is the "width" or duration of the pulse for one single bit.

Since this also has to travel over the distance, we need to calculate
propagation time and simply add the two up.

c should be speed of light or ca 297000km/sec if my memory is ok.
297000km=297000000m

Signal travels at speed of 0.8c so

297000km/sec*0.8= 237600000m/sec

If in one second signal can cross the distance of 237600000meters
than 10 meters travel will last about:
10m/(237600000m/sec)=0.00000004208754 sec. or 0.042usec.

So the time to transfer one single bit is 1.953+0.042 = 1.995usec.

Now all you need to do is figure out how many bits you can transfer
during specified period. It's al basic math...