Transistor Superregenerative Detection

This paper presents thc results of an analytical and experimental study of the principles and mechanism of superregenerative detection using junction transistors. The analysis is based on the study of a transistor oscillator, the criterion of oscillation, and the build-up and decay of oscillation. Due to the dependence of transistor parameters on the operating points, the loop gain of a transistor oscillator can be controlled by changing the emitter current and/or the collector voltage . This property makes the control of a transistor oscillator by an external quenching signal possible. Either the linear mode or the logarithmic mode of detection can be obtained. Self-quenched superregenerative detection also can be obtained. The circuit design and the bias of the transistor have to be such that the initial emitter current is small, but the loop gain of the oscillator is sufficient to start oscillations. Then the bias point of the transistor should be able to change corresponding to the amplitude of oscillation. Typical properties of a superregenerative detector, such as high gain and noise, are characteristic of both vacuum tube and transistor circuits.