摘要 |
A signal being received and superimposed disturbance pulses are taken from a stage of the receiver where the signal is a periodic wave of constant amplitude or of amplitude varying at rates limited by a moderate modulation band, and the signal so picked up is AC-coupled to a diode clamp circuit, the clamp voltage then being amplified to produce a control output for a blanking gate. The forward voltage of the diode is insufficient to put the transistor of the following amplifier into its conducting condition, so that the transistor conducts only when a disturbance pulse extends beyond the limits of the envelope of the sinusoidal signal. By the use of a phase splitter, two identical clamp circuits may be operated to detect disturbance pulses of opposite polarity, and their outputs may be combined to provide blanking control pulses whenever a disturbance pulse of either polarity appears. |