Demodulation device for frequency modulated electrical signals

A demodulation device for demodulation of frequency modulated signals comprising;

• amplitude limiting means having an input for receiving the signal to be demodulated, and a first path for limiting the amplitude of positive alternations of said frequency modulated signals and providing a first output, and a second path for limiting the amplitude of negative alternations of the frequency modulated signal and providing a second output;
• integration means connected to receive the first and second outputs of said amplitude limiting means for integrating the signals therefrom and for integrating said signals with a first and a second time constant;
• said integration means further comprises first and second identical circuits coupled respectively to the first and second outputs of the amplitude limiting means, each circuit comprises a transistor having a base coupled to the corresponding output of the amplitude limiting means, and a capacitor and a charging resistor coupling the base of the transistor to ground and a reference voltage source in such a way that each capacitor is charged by the reference voltage through the charging resistor toward a voltage of predetermined value in accordance with the first time constant, and then discharged across the amplitude limiting means in accordance with a second time constant;
• and a low-pass filter having an input coupled to receive signals from the outputs of the transistors.