A PCB trace $4$ in long and spaced $0\mathrm{.}062$ in from the return conductor is carrying a $10-$MHz$,3\mathrm{.}18-$ns rise time clock signal. Assume the current in the loop is $50$ mA$.$ a$.$ Determine the radiated field strength in dB mV$/$m at the fundamental frequency, when measured at a distance of $3$ m from the board. b$.$ Plot the envelope of the radiated emission from $10$ to $350$ MHz$.$ c$.$ What is the worst$-$case margin against the FCC Class B limit$,$ and at what frequency does it occur?