| 摘要 |
PURPOSE:To generate alternately a pulse at same intervals immune from ultrasonic wave noise in nature, by providing a differentiating circuit operating at steeper leading and trailing edges of the output of an astable multivibrator circuit. CONSTITUTION:The trailing edge of the oscillating waveform at points P, Q of astable multivibrators 5-15 is steep as shown in figs. P, Q, and a pulsive sound wave having a high timing accuracy is generated by utilizing this characteristic. When a potential at a point P rises at a point of time of t1, that is, a transistor(TR)9 turns off, the collector of a TR14 is connected to a base of a TR21 through a resistor 17 and a capacitor 19, the collector potential Q of the TR14 falls down rapidly by the jumping operation. Since the collector of the TR14 is connected to the base of a TR21 through a resistor 17 and a capacitor 19, a base current by steep differentiating characteristic is applied to the base. Thus, the TR21 is made conductive for a moment, a base current is applied to a TR25 for carrier wave generation, the oscillatiang circuit performs oscillation in a very short time and is stopped. As a result, a pulse is generated alternately at same intervals with high accuracy by a simple circuit. |
