Abstract: In order to assure that an alarm signal is transmitted, whether in the case of a true alarm condition or tampering, whether advertent or inadvertent, without any significant increase in power requirements, an alarm radio transmitter system is provided with a supervised loop which controls an electronic switch for connecting the power source (a single battery) to energize the transmitter for a brief interval of time only when an alarm condition or tampering occurs. The supervised loop is part of a bridge circuit also connected to the power source which draws a minimum amount of current therefrom. The alarm radio transmitter system may be remotely located where attention is not available, since the battery need only be infrequently changed.

Abstract: A transistorized superregenerative radio frequency detector which utilizes neither biasing circuits nor a base decoupling capacitor is described herein. The detector is nevertheless self-quenching and operates at a much higher quenching frequency than is the case in conventional superregenerative detectors. Simplifications are afforded over such conventional superregenerative detectors in that the number of components is reduced and the extraction of the demodulated signal as well as the stabilization of the detector is rendered more effective.

Abstract: A phase locked loop system is described which controls and locks the frequency of a UHF transmitter to a desired frequency without the need for complex circuitry. A voltage controlled oscillator provides an output signal at the desired frequency and is controlled by an error signal from a phase detector. A harmonic resonator connected to the phase detector is tuned to a frequency which is approximately equal to the desired frequency but is displaced therefrom slightly in frequency. A reference frequency source at a subharmonic of the desired frequency is coupled to the resonator and the output signal is also coupled to the phase detector so as to generate the error signal which locks the voltage controlled oscillation precisely at the desired frequency.