Generalized frequency modulation
First Claim
1. A receiver for demodulating an information signal from a modulated signal, the receiver comprising:
- a complex mixer for converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component; and
a digital demodulator in communication with the complex mixer, wherein the demodulator comprises at least one processor circuit configured to;
apply a phase differencer for generating an output function in terms of a phase difference of the complex modulated signal, wherein the phase differencer is further configured to;
convert the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time; and
convert the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time, wherein the phase differencer comprises a plurality of cascaded stages, wherein each stage is programmed to convert an input in-phase component to a function of a phase difference of the input in-phase component and to convert an input quadrature component to a phase difference of an input quadrature component, wherein the input in-phase component for the first stage of the plurality of cascaded stages is the first in-phase component and wherein the output of the last stage of the plurality of cascaded stages is the output function; and
apply a four quadrant inverse tangent to the output function to generate the information signal.
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Abstract
A receiver may comprise a complex mixer for converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component. The receiver may further comprise a digital demodulator. The digital demodulator may comprise at least one processor circuit programmed for applying a phase differencer for generating an output function in terms of a phase difference of the complex modulated signal. Applying the phase differencer may comprise converting the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time, and converting the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time. The at least one processor circuit of the digital demodulator may also be programmed for applying a four quadrant inverse tangent to the output function to generate the information signal.
12 Citations
17 Claims
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1. A receiver for demodulating an information signal from a modulated signal, the receiver comprising:
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a complex mixer for converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component; and a digital demodulator in communication with the complex mixer, wherein the demodulator comprises at least one processor circuit configured to; apply a phase differencer for generating an output function in terms of a phase difference of the complex modulated signal, wherein the phase differencer is further configured to; convert the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time; and convert the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time, wherein the phase differencer comprises a plurality of cascaded stages, wherein each stage is programmed to convert an input in-phase component to a function of a phase difference of the input in-phase component and to convert an input quadrature component to a phase difference of an input quadrature component, wherein the input in-phase component for the first stage of the plurality of cascaded stages is the first in-phase component and wherein the output of the last stage of the plurality of cascaded stages is the output function; and apply a four quadrant inverse tangent to the output function to generate the information signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of demodulating a modulated signal to obtain an information signal, the method comprising:
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converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component; and generating an output function in terms of a phase difference of the complex modulated signal, wherein the generating is performed with at least one programmed processor circuit and wherein the generating comprises; converting the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time; and converting the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time applying a plurality of cascaded differencer stages, wherein each stage is programmed to convert an input in-phase component to a function of a phase difference of the input in-phase component and to convert an input quadrature component to a phase difference of an input quadrature component, wherein the input in-phase component for the first stage of the plurality of cascaded stages is the first in-phase component and wherein the output of the last stage of the plurality of cascaded stages is the output function; and applying a four quadrant inverse tangent to the output function to generate the information signal. - View Dependent Claims (10, 11, 12, 13)
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14. A receiver for demodulating an information signal from a modulated signal, the receiver comprising:
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a complex mixer for converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component; and a digital demodulator in communication with the complex mixer, wherein the demodulator comprises at least one processor circuit configured to; apply a phase differencer for generating an output function in terms of a phase difference of the complex modulated signal, wherein the phase differencer is further configured to; convert the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time, wherein the function of the phase difference of the first in-phase component expressed in digital time is given by;
xi+1(n)=xi(n)xi(n−
1)+yi(n)yi(n−
1)wherein; n is digital time; xi+1(n) is the function of the phase difference of the first in-phase component; xi(n) is the in-phase signal; and yi(n) is the quadrature signal; and convert the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time; and apply a four quadrant inverse tangent to the output function to generate the information signal.
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15. A receiver for demodulating an information signal from a modulated signal, the receiver comprising:
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a complex mixer for converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component; and a digital demodulator in communication with the complex mixer, wherein the demodulator comprises at least one processor circuit configured to; apply a phase differencer for generating an output function in terms of a phase difference of the complex modulated signal, wherein the phase differencer is further configured to; convert the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital; and convert the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time, wherein the function of the phase difference of the first quadrature component expressed in digital time is given by;
yi+1(n)=yi(n)xi(n−
1)−
xi(n)yi(n−
1)wherein; n is digital time; yi+1(n) is function of the phase difference of the first quadrature component; xi(n) is the in-phase signal; and yi(n) is the quadrature signal; and apply a four quadrant inverse tangent to the output function to generate the information signal.
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16. A method of demodulating a modulated signal to obtain an information signal, the method comprising:
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converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component; and generating an output function in terms of a phase difference of the complex modulated signal, wherein applying the generating is performed with at least one programmed processor circuit and wherein the generating comprises; converting the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time; and converting the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time, wherein the function of the phase difference of the first in-phase component expressed in digital time is given by;
xi+1(n)=xi(n)xi(n−
1)+yi(n)yi(n−
1)wherein; n is digital time; xi+1(n) is the function of the phase difference of the first in-phase component; xi(n) is the in-phase signal; and yi(n) is the quadrature signal; and applying a four quadrant inverse tangent to the output function to generate the information signal.
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17. A method of demodulating a modulated signal to obtain an information signal, the method comprising:
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converting the modulated signal to a complex modulated signal comprising a first in-phase component and a first quadrature component; and generating an output function in terms of a phase difference of the complex modulated signal, wherein applying the generating is performed with at least one programmed processor circuit and wherein the generating comprises; converting the first in-phase component to a function of a phase difference of the first in-phase component expressed in digital time; and converting the first quadrature component to a function of the phase difference of the first quadrature component expressed in digital time, wherein the function of the phase difference of the first quadrature component expressed in digital time is given by;
yi+1(n)=yi(n)xi(n−
1)−
xi(n)yi(n−
1)wherein; n is digital time; yi+1(n) is function of the phase difference of the first quadrature component; xi(n) is the in-phase signal; and yi(n) is the quadrature signal; and applying a four quadrant inverse tangent to the output function to generate the information signal.
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Specification