Method and apparatus for receiving and despreading a continuous phase-modulated spread spectrum signal using self-synchronizing correlators
First Claim
1. An apparatus for despreading a received continuous phase modulated spread spectrum signal comprising:
- a power divider for dividing a received spread spectrum signal into a real signal and an imaginary signal,a real CPM correlator for correlating said real signal and generating a real I correlation signal and a real Q correlation signal without generating a correlation sequence, said real CPM correlator comprising a self-synchronizing real I digital correlator and a self-synchronizing real Q digital correlator,an imaginary CPM correlator for correlating said imaginary signal and generating an imaginary I correlation signal and an imaginary Q correlation signal without generating a correlation sequence, said imaginary CPM correlator comprising a self-synchronizing imaginary I digital correlator and a self-synchronizing imaginary Q digital correlator,means for combining said real I correlation signal and said imaginary I correlation signal into a final I correlation signal, andmeans for combining said real Q correlation signal and said imaginary Q correlation signal into a final Q correlation signal.
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Abstract
Apparatus and method for despreading a received continuous phase modulated spread spectrum signal includes a power divider for dividing a received spread spectrum signal into a real signal and an imaginary signal. A real CPM correlator demodulates the real signal into I and Q components and separately correlates the real I component and the real Q component without generating a correlation sequence, thereby performing self-synchronizing correlation. Likewise, an imaginary CPM correlator demodulates the imaginary signal into I and Q components and separately correlates the imaginary I component and the imaginary Q component without generating a correlation sequence, thereby performing self-synchronizing correlation. The real I and imaginary I correlation signals are combined into a final I correlation signal, and the real Q and imaginary Q correlation signals are combined into a final Q correlation signal.
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Citations
21 Claims
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1. An apparatus for despreading a received continuous phase modulated spread spectrum signal comprising:
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a power divider for dividing a received spread spectrum signal into a real signal and an imaginary signal, a real CPM correlator for correlating said real signal and generating a real I correlation signal and a real Q correlation signal without generating a correlation sequence, said real CPM correlator comprising a self-synchronizing real I digital correlator and a self-synchronizing real Q digital correlator, an imaginary CPM correlator for correlating said imaginary signal and generating an imaginary I correlation signal and an imaginary Q correlation signal without generating a correlation sequence, said imaginary CPM correlator comprising a self-synchronizing imaginary I digital correlator and a self-synchronizing imaginary Q digital correlator, means for combining said real I correlation signal and said imaginary I correlation signal into a final I correlation signal, and means for combining said real Q correlation signal and said imaginary Q correlation signal into a final Q correlation signal. - View Dependent Claims (2)
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3. A method for despreading a received continuous phase modulated spread spectrum signal comprising the steps of:
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dividing a received spread spectrum signal into a real signal and an imaginary signal, generating a real I signal and a real Q signal from said real signal, correlating said real I signal and said real Q signal and generating a real I correlation signal and a real Q correlation signal without generating a correlation sequence, generating an imaginary I and an imaginary Q signal from said imaginary signal, correlating said imaginary I signal and said imaginary Q signal and generating an imaginary I correlation signal and an imaginary Q correlation signal without generating a correlation sequence, combining said real I correlation signal and said imaginary I correlation signal into a final I correlation signal and combining said real Q correlation signal and said imaginary Q correlation signal into a final Q correlation signal. - View Dependent Claims (4)
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5. An apparatus comprising:
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a power divider connected to a received signal, said power divider having as outputs a real signal and an imaginary signal; a real CPM correlator connected to said real signal, said real CPM correlator generating a real I correlation signal and a real Q correlation signal without comparing said real signal against a correlation sequence; an imaginary CPM correlator connected to said imaginary signal, said imaginary CPM correlator generating an imaginary I correlation signal and an imaginary Q correlation signal without comparing said imaginary signal against a correlation sequence; an I combining circuit connected to said real I correlation signal and to said imaginary I correlation signal, said I combining circuit outputting a final I correlation signal; and a Q combining circuit connected to said real Q correlation signal and to said imaginary Q correlation signal, said Q combining circuit outputting a final Q correlation signal. - View Dependent Claims (6, 7, 8)
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9. A method comprising the steps of:
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dividing a received signal into a real signal and an imaginary signal; generating a real I correlation signal from said real signal without comparing said real signal against a correlation sequence; generating a real Q correlation signal from said real signal without comparing said real signal against a correlation sequence; generating an imaginary I correlation signal from said imaginary signal without comparing said imaginary signal against a correlation sequence; generating an imaginary Q correlation signal from said imaginary signal without comparing said imaginary signal against a correlation sequence; combining said real I correlation signal and said imaginary I correlation signal into final I correlation signal; and combining said real Q correlation signal and said imaginary Q correlation signal into a final Q correlation signal. - View Dependent Claims (10, 11, 12)
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13. An apparatus comprising:
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a power divider having as an input a received spread spectrum signal as outputs a real signal and an imaginary signal; a real demodulator connected to said real signal and to a non-coherent local reference signal, said real demodulator outputting a demodulated real signal; a real correlator connected to said demodulated real signal, said real correlator outputting a real correlation signal without comparing said demodulated real signal with a correlation sequence; an imaginary demodulator connected to said imaginary signal and to said non-coherent local reference signal, said imaginary demodulator outputting a demodulated imaginary signal; an imaginary correlator connected to said demodulated imaginary signal, said imaginary correlator outputting an imaginary correlation signal without comparing said demodulated imaginary signal with a correlation sequence; and a combining circuit connected to said real correlation signal and to said imaginary correlation signal. - View Dependent Claims (14, 15, 16)
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17. A method comprising the steps of:
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dividing a received spread spectrum signal into a real signal and an imaginary signal; demodulating said real signal using a first non-coherent local reference signal, and generating a demodulated real signal thereby; generating a real correlation signal from said demodulated real signal without comparing said demodulated real signal against a correlation sequence; demodulating said imaginary signal using said first non-coherent local reference signal, and generating a demodulated imaginary signal thereby; generating an imaginary correlation signal from said demodulated imaginary signal without comparing said demodulated imaginary signal against a correlation sequence; and combining said real correlation signal and said imaginary correlation signal into a final correlation signal. - View Dependent Claims (18)
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19. An apparatus comprising:
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a power divider connected to a received spread spectrum signal, said power divider having as outputs a real signal and an imaginary signal; a real CPM correlator connected to said real signal, said real CPM correlator generating a real I correlation signal and a real Q correlation signal without comparing said real signal against a correlation sequence; an imaginary CPM correlator connected to said imaginary signal, said imaginary CPM correlator generating an imaginary I correlation signal and an imaginary Q signal without comparing said imaginary signal against a correlation sequence; wherein said real CPM correlator and said imaginary CPM correlator each comprise an I demodulator connected to an I correlator and a Q demodulator connected to a Q-correlator; an I combining circuit connected to said real I correlation signal and to said imaginary I correlation signal, said I combining circuit outputting a final I correlation signal; and a Q combining circuit connected to said real Q correlation signal and to said imaginary Q correlation signal, said Q combining circuit outputting a final Q correlation signal.
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20. An apparatus for despreading a received continuous phase modulated spread spectrum signal comprising:
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a power divider for dividing a received spread spectrum signal into a real signal and an imaginary signal, a real CPM correlator for correlating said real signal and generating a real I correlation signal and a real Q correlation signal without generating a correlation sequence, said real CPM correlator comprising a real I correlation shift register, a real I correlation multiplier connected to a plurality of taps from different chip locations of said real I correlation shift register, a real Q correlation shift register, and a real Q correlation multiplier connected to a plurality of taps from different chip locations of said real Q correlation shift register, an imaginary CPM correlator for correlating said imaginary signal and generating an imaginary I correlation signal and an imaginary Q correlation signal without generating a correlation sequence, said imaginary CPM correlator comprising an imaginary I correlation shift register, an imaginary I correlation multiplier connected to a plurality of taps from different chip locations of said imaginary I correlation shift register, an imaginary Q correlation shift register, and an imaginary Q correlation multiplier connected to a plurality of taps from different chip locations of said imaginary Q correlation shift register, and means for combining said real I correlation signal and said imaginary I correlation signal into a final I correlation signal, and means for combining said real Q correlation signal and said imaginary Q correlation signal into a final Q correlation signal. - View Dependent Claims (21)
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Specification