Circuit and method for automatically sweeping through a plurality of siren modes

摘要

A distinguishable siren sound pattern is produced within an emergency vehicle by automatically alternating the siren sound pattern from among a plurality of distinguishable types of separate siren sound patterns. One of said plurality of distinguishable type of sound patterns may be continuously generated or alternatively through momentary contact in a horn switch, automatically swept among a plurality of the distinguishable siren sound patterns according to a predetermined pattern. In the illustrated embodiment wail, yelp, high-low or hetro siren sound patterns are producible either through microprocessor control or through discretely switched waveform generators. The siren sound pattern is automatically alternated between wail and yelp or between high-low and hetro according to manually switch configurations and momentary activation of a horn ring switch. Repeated activation of the horn ring switch toggles the circuit between a selected continuous siren sound pattern such as a continuous wail or high-low and between an alternating sound pattern as is described.