EP 3415243 A1 20181219 - ACOUSTIC DEVICE FOR WARNING SOUND AND ACOUSTIC SYSTEM
Title (en)
ACOUSTIC DEVICE FOR WARNING SOUND AND ACOUSTIC SYSTEM
Title (de)
AKUSTISCHE VORRICHTUNG FÜR WARNTON UND AKUSTISCHES SYSTEM
Title (fr)
DISPOSITIF ACOUSTIQUE POUR ACOUSTIQUE ET D'AVERTISSEMENT SONORE
Publication
Application
Priority
JP 2017101053 A 20170522
Abstract (en)
An acoustic device for warning sound and an acoustic system are provided which are configured to increase, also when a warning sound at a relatively low frequency is output, a sound pressure level of the warning sound. An acoustic device for warning sound includes a switching circuit and a resonance circuit. A relationship among a frequency fn of an Nth harmonic, a fundamental frequency f0 of a drive voltage V2, and an oscillation frequency f1 is fn-1/2f0 ‰¤ f1 ‰¤ fn+1/2f0, where the Nth harmonic is one harmonic of a plurality of harmonics of the drive voltage V2, a sound pressure level of an output sound from the piezoelectric buzzer at the Nth harmonic being higher than a sound pressure level of the output sound from the piezoelectric buzzer at the fundamental frequency f0.
IPC 8 full level
B06B 1/02 (2006.01); G08B 3/10 (2006.01); G10K 9/122 (2006.01)
CPC (source: EP)
B06B 1/0215 (2013.01); B06B 1/0276 (2013.01); G08B 3/10 (2013.01); G10K 9/122 (2013.01)
Citation (applicant)
JP 2009157447 A 20090716 - HOCHIKI CO
Citation (search report)
- [A] EP 1507603 A1 20050223 - GENT LTD [GB]
- [A] US 4023162 A 19770510 - MURAKAMI FUMIKAZU
Designated contracting state (EPC)
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated extension state (EPC)
BA ME
DOCDB simple family (publication)
EP 3415243 A1 20181219; EP 3415243 B1 20210721; JP 2018194793 A 20181206; JP 6775201 B2 20201028
DOCDB simple family (application)
EP 18172887 A 20180517; JP 2017101053 A 20170522