초록 ▼

Alarm apparatus which generates a repetitive sound wave having at least two pulses of predetermined frequencies within a predetermined interval of time. A resonator generates the clock frequency therefor. The resonator may have a low tolerance of less than about 0.1 percent so that at least two puls

Alarm apparatus which generates a repetitive sound wave having at least two pulses of predetermined frequencies within a predetermined interval of time. A resonator generates the clock frequency therefor. The resonator may have a low tolerance of less than about 0.1 percent so that at least two pulses may be detected by a receiver having a similarly low tolerance so that false triggering of the receiver by other transmitters or background noise may be prevented. A plug is inserted into the alarm housing to maintain circuitry for initiating operation thereof open. Pulling of the plug from the housing allows the circuitry to close to initiate operation of the alarm. A push button is provided on the end of the plug to close the circuitry for initiating operation of the alarm while the plug is inserted into the apparatus. Once the alarm has been initiated, the circuitry is such that the alarm cannot be inactivated except by removal of the internal power source.

대표청구항 ▼

Alarm apparatus comprising electrical circuit means including controller means for generating a variable frequency repetitive sound wave having at least two different predetermined frequencies which occur within a predetermined interval of time, and a resonator for generating a predetermined clock f

Alarm apparatus comprising electrical circuit means including controller means for generating a variable frequency repetitive sound wave having at least two different predetermined frequencies which occur within a predetermined interval of time, and a resonator for generating a predetermined clock frequency for the sound wave.