| 摘要 |
<p>PHF. 79-567 -14- The invention relates to a security memory comprising a transistor oscillator with parallel-series feedback, feedback being provided, via a transformer from a first winding, connected to the collector of the transistor, to a second winding with the same winding direction, connected to the transistor emitter. The memory comprises a power supply input, a control input and an a.c. output as well as an amplifier. In accordance with the invention, this memory, which is designed in accordance with relay security standards, is of the negative control type, i.e. it memorizes the disappearance of a logic signal which is a function of at least one logic variable. To this and its control input is energized with a voltage whose absolute value is smaller than that of the supply voltage of the oscillator and is connected to the collector of the transistor via a diode, which collector in its turn is connected to a capacitor via the first winding, which capacitor starts and sustains the oscillation. The invention is used for railwaysignalling.</p> |
