A multi-frequency alarm (10) generates a narrow band noise (MFA-87, -97, 102, -107) warning of a presence of a vehicle. The alarm includes noise signal circuitry (30) generating a pseudorandom bit stream to produce a noise signal that exhibits a multi-frequency spectrum; an active low-pass filter (40) receiving the noise signal and producing a narrow band noise signal, the active low-pass filter configured to establish for the narrow band noise signal spectral characteristics exhibiting a high-frequency noise signal magnitude roll-off that attenuates frequencies greater than 4 kHz; an audio amplifier (50) producing an amplified narrow band noise signal; and an audio speaker (60) responsive to the amplified narrow band noise signal and configured to emit narrow band noise sound derived from the narrow band noise signal.
MULTI-FREQUENCY ALARM FOR EMITTING NARROW BAND NOISE
2015-09-03
Patent
Electronic Resource
English
IPC: | B60Q ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL , Anordnung von Signal- oder Beleuchtungsvorrichtungen, deren Einbau oder Halterung oder deren Schaltkreise bei Fahrzeugen allgemein |
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