| 摘要 |
An audio range siren detector utilizes an audio pickup including an A.G.C. amplifier, a plurality of electronic active filters having closely spaced resonant frequencies such as 800, 825, 850 timing means responsive to an actuating signal from one of the filters for generating a time slot signal of short duration, gating means responsive to each of the filter means for producing an actuating signal, control logic responsive to the occurrence of all actuating signals within the time slot to produce output denoting a valid siren signal, and relay means for setting traffic lights to emergency condition.
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