Method and device for discriminating difference frequency of two pulse trains

A device for determining the frequency difference of first and second pulse trains, said device comprising

• a separator of odd and even pulses, said separator having an input which functions as a first input of said device and first and second outputs, a first pulse train being applied to said input;
• a first AND gate having a first input electrically connected to the first output of said separator, a second input and an output;
• a second AND gate having a first input electrically connected to the second output of said separator, a second input and an output;
• an OR gate having a first input electrically connected to the output of said first AND gate, a second input electrically connected to the output of said second AND gate and an output;
• a third AND gate having a first input, a second input electrically connected to the output of said OR gate and an output which functions as a first output of said device;
• a 2:1 pulse frequency divider having an input which functions as a second input of said device and an output electrically connected to the first input of said third AND gate, a second pulse train being applied to said input, the output of said third AND gate providing a signal of the frequency difference of said first and second pulse trains;
• and
• a flip-flop having an input electrically connected to the output of said third AND gate, a first output electrically connected to the second input of said first AND gate, said first output functioning as a second output of said device, and a second output electrically connected to the second input of said second AND gate, said second output functioning as a third output of said device.