System for demodulating angle-modulated signals

A system for demodulating angle-modulated signals comprising:

• first-order differentiation means supplied with an angle-modulated signal;
• first amplitude limiting means for limiting the amplitude of the output signal of said first-order differentiation means;
• tracking band-pass filtering means responsive to said angle-modulated signal and having a pass band with a center frequency which is controlled responsive to a control signal;
• second amplitude limiting means for limiting the amplitude of the output signal of said tracking band-pass filtering means;
• phase comparing means responsive to the output signals of said first and second amplitude limiting means for producing an error signal in accordance with the phase difference between said output signals;
• means responsive to said error signal of said phase comparing means for controlling said tracking band-pass filtering means;
• and
• means responsive to said error signal for deriving a demodulated signal.

A system for demodulating angle-modulated wave signals comprising:

• second-order differentiation means supplied with an angle-modulated signal;
• first amplitude limiting means for limiting the amplitude of the output signal of said second-order differentiation means;
• tracking band-pass filtering means responsive to said angle-modulated wave signal and having a pass band with a center frequency which is controlled by a control signal;
• first-order differentiation means responsive to the output of said tracking band-pass filtering means;
• second amplitude limiting means for limiting the amplitude of the output signal of said first-order differentiation means;
• phase comparing means responsive to the outputs of said first and second amplitude limiting means for producing an error signal in accordance with the phase difference between the output signals of said first and second amplitude limiting means;
• means responsive to said error signal for controlling said tracking band-pass filtering means;
• and
• means responsvie to said error signal for deriving a demodulated signal.