| 摘要 |
PURPOSE: To form a simple detection circuit operated without the need for any automatic control by combining a rectifier circuit having a capacitor being a peak detector with a biased transistor(TR) to eliminate noise so as to compress a dynamic range. CONSTITUTION: A full wave rectifier circuit PDR is designed as a differential amplifier having emitter follower outputs T8, R16 and bases of TRs T3, T4 at its input stage and acts like a peak detector. Since the peak detector is provided, a sharpness of a most intensified signal is especially detected, and in this case, a dynamic signal range is much reduced. Furthermore, in order to exclude noise in existence in the rectified signal, a biased TR T7 is provided to the detector. In the case that only noise is in existence and both the T5, T6 are not highly conductive, the T7 is conductive and the noise is excluded via a collector-emitter path. Thus, the dynamic range is compressed by using peak detection and noise suppression functions of requirements. |
