On and off, ones and zeros--binary is beautiful, but moving the bits at high speed gets a little tricky.  A bit of data is represented by each transition from zero to one, or from one to zero; the faster you can make these transitions, the more bits of data you can move per unit of time.

The base frequency for a data rate of X bits per second is X/2 Hertz (cycles per second).  This is due to the fact that for each cycle there is a rising and falling edge, each of which is an opportunity for a bit of data to be exchanged.  Unfortunately, the slope of that X/2 Hertz waveform is not adequate for bit transfer, as the chips that process the signals need them to stay at the one or zero threshold voltage (yes, even the “one” and “zero” voltage levels is fuzzy) for a certain amount of time to register the data state.b2ap3_thumbnail_Part-7-Image-1_20131212-145142_1.jpg

For this reason, higher frequency energy must be present to make the transition from zero to one more quickly.  The ability of the connector and the total interconnect system to support higher frequencies determines the data rate.  The image below provides a visual image of how multiple sine waves of varying frequency can be combined to generate waveforms similar to square waves.b2ap3_thumbnail_Part-7-Image-2.jpg

Stay tuned for Part 8 where we look at the rocky road of connectivity.