Abstract If square wave generation in response to a frequency shift base band signal is to be correct, the value of the threshold or trigger control voltage has to bear a definite relationship at each moment to the zero crossings of the alternating voltage component of the baseband signal. This is achieved by two resistors connected in series between a frequency demodulator and the output of a square wave generator, with the junction of the resistors being connected to a first non-phase inverting input of the generator, a third resistor connected between the demodulator and a second phase-inverting input of the generator, a fourth resistor connected between a reference potential and the second input, and an integrating capacitor connected between the reference potential and the junction of the first and second resistors.
A circuit arrangement for correcting asymmetrical distortion, originating infrequency faults, in a demodulator for frequency shift modulated signals comprising: a frequency demodulator for supplying a base band signal; a conversion circuit for converting said base band signal to a square wave signal, said circuit having an output, a first phase inverting input, and a second non-phase inverting input; a first resistor and a second resistor coupled in series with respect to each other, the output of said demodulator and the output of said circuit; the junction of said first and second resistors being coupled to said second input of said circuit; a third resistor coupled between the output of said demodulator and said first input of said circuit; a reference potential; a fourth resistor coupled between said reference potential and said first input of said circuit; and a capacitor for integrating purposes coupled between said reference potential and said junction of said firSt and second resistors.
Claim 2
Dependent Claim
156 words
A circuit arrangement for correcting asymmetrical distortion, originating infrequency faults, in a demodulator for frequency shift modulated signals comprising: a frequency demodulator for supplying a base band signal; a conversion circuit for converting said base band signal to a square wave signal, said circuit having an output, a first phase inverting input, and a second non-phase inverting input; a first resistor and a second resistor coupled in series with respect to each other, the output of said demodulator and the output of said circuit; the junction of said first and second resistors being coupled to said second input of said circuit; a third resistor coupled between the output of said demodulator and said first input of said circuit; a reference potential; a fourth resistor coupled between said reference potential and said first input of said circuit; and a capacitor for integrating purposes coupled between said reference potential and said junction of said firSt and second resistors.
Claim 3
Dependent Claim
52 words
A circuit arrangement according to claim 1, further including a potentiometer having one of its permanent terminals coupled to the output of said demodulator, the other of its permanent terminals coupled to said reference potential and its movable terminal coupled to one of said first and second resistors and said third resistor.
Claim 4
Dependent Claim
14 words
A circuit arrangement according to claim 2, wherein said reference potential is 0 volts.