Wide band frequency discriminator utilizing a constant amplitude equalizer network

Claim 2

A wide band frequency discriminator comprising: A. a wide band phase detector having first and second input terminals and an output terminal; B. an all pass equalizer network having input and output terminals and having a transfer function such that the output signal from the network has its phase shifted as a predetermined linear function of the frequency of the input signal to the network over a limited range and as a nonlinear function over an extended frequency range; C. means connecting the output terminal of said network to the first input terminal of said phase detector; and D. means to apply a frequency modulated signal simultaneously to the input terminal of said network and directly to the second input terminal of said phase detector.

Claim 3

A wide band frequency discriminator comprising: A. a wide band phase detector having first and second input terminals and an output terminal; B. an all pass lattice equalizer network having input and output terminals and having a transfer function such that the output signal from the network has its phase shifted as a predetermined linear function of the frequency of the input signal to the network over a preselected frequency range; C. means connecting the output terminal of said network to the first input terminal of said phase detector; and D. means to apply a frequency modulated signal simultaneously to the input terminal of said network and directly to the second input terminal of said phase detector.

Claim 4

A wide band frequency discriminator comprising: A. a wide band phase detector having first and second input terminals and an output terminal; B. an all pass lattice equalizer network having input and output terminals and having a transfer function such that the output signal from the network has its phase shifted as a predetermined linear function of the frequency of the input signal to the network over a preselected frequency range; C. means connecting the output terminal of said network to the first input terminal of said phase detector; and D. means to apply a frequency modulated signal simultaneously to the input terminal of said network and directly to the second input terminal of said phase detector.

Claim 5

Apparatus for producing a DC voltage which is a measure of the deviation of the frequency of an input signal from a preselected carrier frequency comprising: A. an all pass equalizer network having input and output terminals; B. means to apply a frequency modulated signal to said input terminal; C. impedance elements in said network selected to produce a network transfer function such that the network produces a 90* phase shift in its output signal when the frequency of said input signal is equal to said carrier frequency, and produces a phase shift less than or greater than 90* according to whether the frequency of said input signal is less than or greater than said carrier frequency as a linear function; D. a wide band phase detector circuit which has first and second input terminals and an output terminal for producing a DC output voltage of one polarity when the phase difference between its inputs is less than 90* , an output of the opposite polarity when said phase difference is greater than 90* , and an output of zero amplitude when said phase difference is equal to 90* ; E. means to apply the output signal from said network to the first input terminal of said phase detector; and F. means to apply a portion of said frequency modulated signal applied to said input of the network directly to said second input terminal of said phase detector.

Claim 6

Apparatus for producing a DC voltage which is a measure of the deviation of the frequency of an input signal from a preselected carrier frequency comprising: A. an all pass equalizer network having input and output terminals; B. means to apply a frequency modulated signal to said input terminal; C. impedance elements in said network selected to produce a network transfer function such that the network produces a 90* phase shift in its output signal when the frequency of said input signal is equal to said carrier frequency, and produces a phase shift less than or greater than 90* according to whether the frequency of said input signal is less than or greater than said carrier frequency as a linear function; D. a wide band phase detector circuit which has first and second input terminals and an output terminal for producing a DC output voltage of one polarity when the phase difference between its inputs is less than 90* , an output of the opposite polarity when said phase difference is greater than 90* , and an output of zero amplitude when said phase difference is equal to 90* ; E. means to apply the output signal from said network to the first input terminal of said phase detector; and F. means to apply a portion of said frequency modulated signal applied to said input of the network directly to said second input terminal of said phase detector.

Claim 7

A wide band frequency discriminator comprising: A. a wide band phase detector having first and second input terminals and output terminals; B. on all pass equalizer network having input and output terminals and having a transfer function such that the output signal from the network has its phase shifted as an approximately linear function of the frequency of the input signal to the network at least over a preselected frequency range, said transfer function being such that the tangent to the curve expressing the value of phase shift Beta as a function of frequency f at a predetermined point on the curve in said approximately linear portion is defined by the equation Beta m (fa) wherein the absolute value of a is greater than zero and wherein the value of m can be predetermined independently of the value of a; C. means connecting the output terminal of said network to the first input terminal of said phase detector; and D. means to apply a frequency modulated signal simultaneously to the input terminal of said network and directly to the second input terminal of said phase detector.

Claim 8

A wide band frequency discriminator comprising: A. a wide band phase detector having first and second input terminals and output terminals; B. on all pass equalizer network having input and output terminals and having a transfer function such that the output signal from the network has its phase shifted as an approximately linear function of the frequency of the input signal to the network at least over a preselected frequency range, said transfer function being such that the tangent to the curve expressing the value of phase shift Beta as a function of frequency f at a predetermined point on the curve in said approximately linear portion is defined by the equation Beta m (fa) wherein the absolute value of a is greater than zero and wherein the value of m can be predetermined independently of the value of a; C. means connecting the output terminal of said network to the first input terminal of said phase detector; and D. means to apply a frequency modulated signal simultaneously to the input terminal of said network and directly to the second input terminal of said phase detector.

Claim 9

A wide band frequency discriminator comprising: A. a wide band phase detector having first and second input terminals and an output terminal, said phase detector having a zero output when a phase difference of 90* exists between signal applied to said input terminals; B. an all pass equalizer network having input and output terminals and composed of elements which provide a network transfer function such that the output signal from the network has its phase shifted as a predetermined function of the frequency of the input signal to the network over a preselected frequency range, said predetermined function being such that the tangent to the curve expressing the value of phase shift Beta as a function of frequency f at a preselected operating point on the curve corresponding to a frequency f1 is defined by the equation Beta m (fa) wherein the absolute value of a is greater than zero and wherein the value of m is greater than one and can be predetermined independently of the value of a, said phase shift Beta having a value of 90* at said frequency f1; C. means connecting the output terminal of said network to the first input terminal of said phase detector; and D. means to apply a frequency modulated input signal simultaneously to the input terminal of said network and directly to the second input terminal of said phase detector to produce a DC output voltage from said phase detector which is proportional to the deviation of the frequency of said input signal from said frequency f1 at said operating point within a preselected range of deviation.

Claim 10

A wide band frequency discriminator comprising: A. a wide band phase detector having first and second input terminals and an output terminal, said phase detector having a zero output when a phase difference of 90* exists between signal applied to said input terminals; B. an all pass equalizer network having input and output terminals and composed of elements which provide a network transfer function such that the output signal from the network has its phase shifted as a predetermined function of the frequency of the input signal to the network over a preselected frequency range, said predetermined function being such that the tangent to the curve expressing the value of phase shift Beta as a function of frequency f at a preselected operating point on the curve corresponding to a frequency f1 is defined by the equation Beta m (fa) wherein the absolute value of a is greater than zero and wherein the value of m is greater than one and can be predetermined independently of the value of a, said phase shift Beta having a value of 90* at said frequency f1; C. means connecting the output terminal of said network to the first input terminal of said phase detector; and D. means to apply a frequency modulated input signal simultaneously to the input terminal of said network and directly to the second input terminal of said phase detector to produce a DC output voltage from said phase detector which is proportional to the deviation of the frequency of said input signal from said frequency f1 at said operating point within a preselected range of deviation.