| 摘要 |
1,136,153. Detecting signal peaks. HUGHES AIRCRAFT CO. 24 Oct., 1966 [24 Jan., 1966], No. 47499/66. Heading H3T. A circuit for detecting the time of occurrence of the maximum amplitude of an input signal comprises a differentiating circuit 14 feeding a transistor 22 acting as a threshold device. In Fig. 1 the transistor is biased to cut off by the voltage drop across diode 32. With an input e in comprising half a cycle of a sine wave the voltage e d across resistance 18 is a positive curve followed by a negative curve, with a zero crossing occurring approximately at the peak of the input signal. At this zero crossing the transistor conducts and the output e o at terminal 12 is a rectangular pulse starting at the time of the zero crossing. In a modification, Fig. 2 (not shown), the emitter is earthed and the biasing circuit 28, 34 and 32 is connected to the end of resistance 18. The diode and transistor are connected so that temperature affects them equally and the circuit is insensitive to temperature variations. |
