HI,
I am revising for an avionics exam and I have a question that is probably quite simple.
In my notes, I have two diagrams of data stream formats: bi-polar RTZ format and Manchester bi-phase.
The two graphs showing voltage with time have different periods, the RTZ fromat has a bit-time of 10us (on an ARINC 429 databus) and the Manchester format has a bit time of 1us (on a MIL-STD-1553B databus). Is the bit-time difference related to the format or the type of databus?
Also, can anyone explain why a manchester bi-phase formatted signal needs a higher bandwidth than an asynchronous communictaion?
When I think of the bandwidth, I am guessing that one oscilation is represented from the voltage going from one value to another and back to that value. I think the frequency of the RTZ format is fixed because the voltage returns to zero at the end of each bit, but the Manchester format has two frequencies, imagining two logic 'ones' having a frequency, and a 'one' and a 'zero' in succesion having half of that frequency.