Interference signals detector for receiver - has parallel RC circuit between transistor emitter and frame, with large time constant

摘要

The receiver has an electronic interference suppression device as in 2613470 with a gate in the signal path. Useful signal containing interference pulses are applied through a clamping circuit to an amplifying transistor which amplifies pulse-like signals, but is ineffective for sinusoidal signals. The signal with interference pulses is applied to the base of an emitter follower, whose emitter is connected through a capacitor to the base of a second transistor connected to frame through a diode. The diode forward direction is in parallel with the base-emitter path of the second transistor. The emitter of the amplifying second transistor (T2) is connected through a parallel RC circuit (R5, C4) to frame. The RC circuit time constant is large in comparison with the interference pulse rise time.