Demodulator for automatic gain control in automatic DF receivers - has nonlinear component at input and RC circuit with small time constant

摘要

The demodulator is fitted with a second nonlinear device at the output and there is an RC circuit with a large time constant. A transistor connected is in parallel with the output capacitor controlled from a centre tapping of a series circuit consisting of a resistor and a capacitor; other terminals of this resistor and capacitor are connected to the terminals of the nonlinear component at the output. The transistor (T1), resistor (R1) and capacitor (C1) form the first stage of the demodulator and have a small time constant. The second stage consists of a diode (1) a resistor (R2) and a capacitor (C2) and has a large time constant and the capacitor (C3) acts as a timing device.