Abstract A communication system for an emergency vehicle including a provision for selectively producing plural automatically and manually controlled siren sounds, the sound broadcast of radio reception and the sound amplification of the input to a microphone. A complete momentary-contact, pushbutton console may be employed, if desired, by short circuiting all the inputs to ground except that corresponding to the mode of operation selected. Start up instability is also eliminated. A selector pushbutton performs the dual function of manual siren control. Negative feedback from the speaker is provided selectively for radio and public address system use. Common use of components reduces cost and complexity. For example, common use of a voltage controlled oscillator, two amplifier stages, a driver and a speaker assembly is made. Radio input is turned on by an alternate action switch. As described in the specification, the action of ''''turning on'''' the radio shorts out all siren functions by firing silicon controlled rectifiers. The microphone input is turned on by pushing the ''''push to talk'''' switch thereon. This action fires all the siren shorting silicon controlled rectifiers through a pulse amplifier.
Inventors
👤 Gordon S Carroll
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-04 11:29
CPC Classifications
G; G08; G08B; G08B3/00; G08B3/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
219 words
A sound communication system comprising: amplifier means having at least first, second and third input leads, and an output lead, said amplifier means being adapted to produce an output signal on said output lead thereof which is directly proportional to the sum of the signals on said first, second and third input leads thereof; alternate means selectively operable to impress a variable audio frequency signal on said amplifier means first input lead; a source having an output lead, said source being adapted to produce audio frequency signals on said output lead thereof; a double-pole, double-throw switch having first and second ganged poles and first and second contacts respectively engageable by said first and second poles; means responsive to engagement of said first pole with said first contact for connecting said source output lead to said amplifier means second input lead; and output means having an input lead connected from said amplifier means output lead for broadcasting audible sound in accordance with the amplitudes and frequencies of the A.C. components in signal appearing on the said output lead of said amplifier means, said output means including a speaker having a negative feedback lead, said second pole and second contact forming a single-pole switch which is connected iN series from said negative feedback lead to said amplifier means third input lead.
Claim 2
Dependent Claim
219 words
A sound communication system comprising: amplifier means having at least first, second and third input leads, and an output lead, said amplifier means being adapted to produce an output signal on said output lead thereof which is directly proportional to the sum of the signals on said first, second and third input leads thereof; alternate means selectively operable to impress a variable audio frequency signal on said amplifier means first input lead; a source having an output lead, said source being adapted to produce audio frequency signals on said output lead thereof; a double-pole, double-throw switch having first and second ganged poles and first and second contacts respectively engageable by said first and second poles; means responsive to engagement of said first pole with said first contact for connecting said source output lead to said amplifier means second input lead; and output means having an input lead connected from said amplifier means output lead for broadcasting audible sound in accordance with the amplitudes and frequencies of the A.C. components in signal appearing on the said output lead of said amplifier means, said output means including a speaker having a negative feedback lead, said second pole and second contact forming a single-pole switch which is connected iN series from said negative feedback lead to said amplifier means third input lead.
Claim 3
Dependent Claim
14 words
The invention as defined in claim 1, wherein said source includes a radio receiver.
Claim 4
Dependent Claim
13 words
The invention as defined in claim 1, wherein said source includes a microphone.
Claim 5
Dependent Claim
31 words
The invention as defined in claim 3, wherein said microphone is connectible to said amplifier means second input lead by said first pole and said first contact through a volume potentiometer.