Transmitter search sweep circuit - has polarity-dependent switch control circuit suppressing voltages of inappropriate polarity

摘要

The output of a differential amplifier is connected to a control input of an electronic switch for starting and stopping the search sweep via a voltage limiting arrangement dependent on polarity. The arrangement applies to the electronic switch, as stop pulses, portions of one polarity of a voltage of S-form occurring at the output of the differential amplifier during the sweep and suppresses portions of the opposite polarity which could act a control voltages for the electronic switch. The collectors of two transistors are connected together via a series circuit of two resistors and a diode. One terminal of the diode is coupled via a capacitor with the base of a transistor which is coupled with another transistor to form a bistable flip-flop.