Work the following problems.
1)Express the speed of light…
a. In ps/cm
b. In ns/foot
2)Consider a signal with a rise time of 200 ps.
a. What is the knee frequency of the signal?
b.Consider the signal on a trace over an insulator withεr = 4. How long is the rising edge, in inches?
c.How long does a trace have to be in order to be considered“distributed�
3)The same signal is routed on a circuit board. The outputcapacitance is 15 pF and the resistance of the gate that drives thesignal is 20 ohms.
a. What is the risetime of the signal, taking into account the Rand C of the output driver?
b. What is the new knee frequency, after RC filtering?
4) A circuit board is being designed with εr = 4.2. Atrace is laid out with a length of 2.5 cm.
a.What risetime is needed for the trace to be considereddistributed and not lumped?
b.What knee frequency corresponds to the risetime you calculatedin a?
c.The signal has a risetime of 50 ps. What RC (that is, an RCtime constant of what value) is needed to slow the signal down tothe risetime you calculated in a?
d.The load capacitance of the signal is 20 pF. What value ofresistor should be inserted onto the line to obtain the value of RCyou calculated in c?
