On 03/17/2015 03:43 PM, Carlos E. R. wrote:
All digital electronics are basically analog underneath. Assume a supply voltage of 5 volts. Typically it is said that a #0 is zero volts, and a #1 is 5 volts. Not true. It is rather something like "between 0 and 2 volts it is considered a zero, and above 3 volts it is considered a one". Notice that there is a gray undefined area in the middle.
Basically, as speeds rise the voltages may not have time to reach a value that can clearly be interpreted as a one or a zero.
Detailed spec sheets such as the classic Texas Instruments TTL handbook had a lot if information on this. I'm surd a bit of googling will show up more modern, more detailed studies. Its surely been the subject of one of the many PhD thesis we see each year. Then there are the capacitive effects on rise times and the inductive effects of the PCB traces acting as 'transmission lines'. After all, we are talking abut GigaHertz frequencies. -- A: Yes. > Q: Are you sure? >> A: Because it reverses the logical flow of conversation. >>> Q: Why is top posting frowned upon? -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org