Patent ID: 8024679

Claim:
A method in a computer-aided design system for generating a functional design model of an apparatus for handling a signal, comprising: using a computer in: generating a functional representation of at least one common signal node having a first conductor operable to conduct a first signal; generating a functional representation of a first circuit coupled to said common signal node, operable to receive said first signal; generating a functional representation of a signal-handling element coupled to said first conductor, said signal-handling element having an isolating circuit coupled to said first conductor; generating a functional representation of a second conductor operable to conduct an output of said isolating circuit; and generating a functional representation of a signal-handling circuit coupled to said second conductor, said signal-handling circuit operable to perform a signal-handling function in response to said output of said isolating circuit, wherein said isolating circuit is operable to isolate said common signal node and said first circuit from said second conductor and said signal-handling circuit, wherein said step of generating a functional representation of a signal-handling element further includes generating a functional representation of a hysteresis comparator included in said signal-handling element, wherein said isolating circuit includes an input transistor of said hysteresis comparator, said input transistor being coupled to receive input from said common signal node and to provide output onto said second conductor, said hysteresis comparator further including a portion included in said signal-handling circuit, said portion including comparator circuitry responsive to said output on said signal conductor, and wherein said functional representation of said common signal node includes a pair of first conductors, said second conductor includes a pair of said second conductors, said functional representation of said first communication signal includes a differential communication signal conducted by said pair of first conductors, and said functional representation of said signal-handling element includes a signal detector, said functional representation of said isolating circuit includes a front stage receiver element of said signal detector operable to regenerate said differential communication signal as a pair of regenerated signals on said pair of second conductors, and said functional representation of said signal-handling circuit of said signal detector includes circuitry operable to produce time-averaged signals from said regenerated signals, said signal-handling circuit being operable in response to said time-averaged signals to detect presence or absence of said first communication signal.