Abstract: An audible tone is generated and attenuated over a wide frequency range, such as throughout the human audible range, the tone selectively being of short duration. During a tone period a digital representation of the sine of a requested tone frequency and amplitude is generated. During an attenuation period a digital representation of a moderately disturbed but continuous sine of decreasing amplitude is generated. During a decay period a digital representation of a continuous function which decays to zero from the zero approach point of the sine half wave is generated.

Abstract: A method of designing the clocking circuitry of an integrated circuit chip. The load sinks are assigned to clock nets, each clock net having less then a maximum load. The first step is selecting a pair of clock nets for improvement. Next, a subset of the load sinks of the pair of clock nets are assigned to each clock net. Thereafter, the unassigned load sinks are assigned in all possible combinations to each of the pair of clock nets. A penalty function for each load sink assignment, and the assignment having the best penalty function is kept.