Abstract: A method of admitting and routing switched virtual circuit requests in a network first finds a set of routing paths on which a requested VC may be routed by using a two step process. The method uses a cost function based on a parameter related to the number of hops in a subset of VC connections previously made in the network to determine potential routing paths on which the VC can be routed at a cost below a specified threshold. The method next checks to determine which potential routing paths comprise links and nodes with sufficient resources to accommodate the request. Paths satisfying both steps are output as a set of routing paths and then a second criterion is used to select a path from the set on which to route the request. In a distributed routing system, the inventive method uses a local network state to determine the cost function and the set of routing paths.

Abstract: A transducer signal waveshaping system is provided, in which a signal excitation circuit includes a non-linear device. The resulting circuit produces a short input pulse, which allows a piezoelectric transducer to transmit a shortened output signal having distinct waveshape characteristics. The resulting waveshaped output signal, typically an ultrasonic signal, provides a measurable time-dependent signal that is particularly suited for data entry systems, such as for movable transmitter pens and white boards. The location of the transmitter pen in relation to the writing area of a white board can be determined, using the periodic transmission of the waveshaped output signals. Alternative embodiments include additional circuit elements, which allow the resulting waveshaped output signal to include even more distinctive waveform features.