Ambient noise frequency responsive audible vehicle alarm

Claim 2

Audible signal generating apparatus for a vehicle operated in the presence of ambient noise comprising means including an electroacoustic transducer for generating an audible signal, means sensing the frequency of the ambient noise, and electric signal generating means electrically coupled to said transducer and responsive to said frequency-sensing means, said signal generating means providing first electric signals as a function of the sensed frequency of the ambient noise causing said transducer to emit an audible signal responsive to the ambient noise and including at least one audio frequency component distinct from the frequency of the ambient noise.

Claim 3

Apparatus according to claim 1 wherein the generating means comprises electric frequency comparing means having a first output signal responsive to the frequency distribution of the ambient noise, and frequency-generating means electrically coupled to said comparing means and said transducer, and having a second output signal of a frequency distinct from the frequency of the ambient noise level.

Claim 4

Apparatus according to claim 2 wherein said frequency-generating means comprises means having a high frequency output and means having a low frequency output, and wherein said comparing means energizEs one of said high and low frequency output means.

Claim 5

Apparatus according to claim 3, including means electrically coupled to said comparing means and to said transducer and separating second electric signals from said frequency sensing means into high and low band frequency electric signals, and wherein said comparing means is responsive to the relative magnitude of said high and low frequency signals.

Claim 6

Apparatus according to claim 1 wherein said frequency sensing means provides input signals for said signal generating means which are responsive to the relative intensity of the frequencies detected in the ambient noise, wherein said electric signal generating means includes means having a high audio frequency output, means having a low audio frequency output, means separating high frequency input signals from low frequency input signals, and means measuring the relative intensity of the high and low frequency inputs and actuating said means having the high audio frequency output in response to a greater intensity of the low frequency input signals, as compared with the high frequency input signals, and the means having the low audio frequency output in response to greater intensity of the high frequency input signals, as compared with the low frequency input signals, whereby the audible signal generated by said transducer has a frequency range distinct from the frequency of the ambient noise.

Claim 7

Apparatus according to claim 1 wherein the electric signal generating means includes means for generating variable frequency first electric signals, and means responsive to the frequency of signals received from the said frequency-sensing means for varying the frequency of said variable frequency signal generating means so that the frequency of the signals from the variable frequency signal generating means differs from the frequency of the ambient noise.