Emergency signal warning system

Claim 1

A system for detecting the presence of emergency siren sound signals varying in frequency in a predetermined manner over a predetermined frequency range, said system including in combination: a source of input signals representative of said emergency siren sound signals; convertor means coupled with said source of input signals for providing a digital signal output in the form of signal bits representative of said input signals; digital signal processor means coupled with said convertor means for continuously processing and storing the output of said convertor means into groups of predetermined numbers of bits of said digital signal output; control means responsive to the storage of successive "N" (where "N" is a positive integer) groups of said predetermined numbers of bits for processing each of said "N" groups of bits and providing an output signal representative of the frequency of said signals at the source of input signals for each of said "N" groups of bits; averaging means for averaging the output signals from said control means to provide a first comparison output signal representative of the average value of the output signals from said control means; means coupled with said control means for determining the peak values of the output signals from said control means to produce a second comparison output signal; first comparison means with first and second inputs coupled to continuously receive said first and second comparison output signals to produce a continuous sequence of flag output signals whenever an emergency siren sound signal is present; reference signal pattern means; and second comparison means coupled with the output of said first comparison means and said reference signal pattern means for continuously comparing successive flag output signals from said first comparison means with said reference signal pattern means for providing an alarm output signal in response to a predetermined comparison correlation.

Claim 2

A system for detecting the presence of emergency siren sound signals varying in frequency in a predetermined manner over a predetermined frequency range, said system including in combination: a source of input signals representative of said emergency siren sound signals; convertor means coupled with said source of input signals for providing a digital signal output in the form of signal bits representative of said input signals; digital signal processor means coupled with said convertor means for continuously processing and storing the output of said convertor means into groups of predetermined numbers of bits of said digital signal output; control means responsive to the storage of successive "N" (where "N" is a positive integer) groups of said predetermined numbers of bits for processing each of said "N" groups of bits and providing an output signal representative of the frequency of said signals at the source of input signals for each of said "N" groups of bits; averaging means for averaging the output signals from said control means to provide a first comparison output signal representative of the average value of the output signals from said control means; means coupled with said control means for determining the peak values of the output signals from said control means to produce a second comparison output signal; first comparison means with first and second inputs coupled to continuously receive said first and second comparison output signals to produce a continuous sequence of flag output signals whenever an emergency siren sound signal is present; reference signal pattern means; and second comparison means coupled with the output of said first comparison means and said reference signal pattern means for continuously comparing successive flag output signals from said first comparison means with said reference signal pattern means for providing an alarm output signal in response to a predetermined comparison correlation.