EP 0025537 B1 19840620 - WARNING SIGNAL GENERATOR FOR FEEDING A PRESSURE CHAMBER LOUDSPEAKER
Title (en)
WARNING SIGNAL GENERATOR FOR FEEDING A PRESSURE CHAMBER LOUDSPEAKER
Publication
Application
Priority
DE 2936981 A 19790913
Abstract (en)
[origin: EP0025537A1] 1. Warning signal generator for supplying a signal to a compression driver projector horn whose sound propagation range lies above a preset fundamental frequency of a warning signal to be propagated by a compression driver projection horn loudspeaker, and the aforementioned warning signal contains a great many components of harmonics that occur in the sound projection range of the compression driver projection horn loudspeaker, characterized by the warning signal is a composite signal formed to be a square wave signal at constant amplitude and comprising a first square wave signal (4f) at the frequency of the fourth harmonic and a second square wave signal (2f) at the frequency of the second harmonic, whereby the fundamental frequency (f) is the changeover switching frequency used for switching between the first and second (4f, 2f) square wave signals, so that at the output (A) of the warning signal generator, the signal alternates at the same periodic rate of change of the fundamental frequency (f), and during each first half-period of the fundamental frequency, the first square wave signal appears and during each second half-period of the fundamental frequency, the second square wave signal appears, with the consequence that the warning signal appears as the composite of the two (Fig. 2d).
IPC 1-7
IPC 8 full level
G08B 3/10 (2006.01); G10K 9/12 (2006.01); G10K 15/02 (2006.01); H04R 3/00 (2006.01)
CPC (source: EP)
G08B 3/10 (2013.01); G10K 15/02 (2013.01)
Designated contracting state (EPC)
AT BE CH FR GB IT LI LU NL SE
DOCDB simple family (publication)
EP 0025537 A1 19810325; EP 0025537 B1 19840620; AT E8081 T1 19840715; DE 2936981 A1 19810319; DE 2936981 C2 19850822; DK 149671 B 19860901; DK 388480 A 19810314; FI 802589 A 19810314; NO 149367 B 19831227; NO 149367 C 19840404; NO 802696 L 19810316
DOCDB simple family (application)
EP 80105148 A 19800829; AT 80105148 T 19800829; DE 2936981 A 19790913; DK 388480 A 19800912; FI 802589 A 19800818; NO 802696 A 19800911