Single sideband receiver with pilot-based feed forward correction for motion-induced distortion
First Claim
1. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, both components having said distortion effects therein as received, the improvement comprisingmeans (17) for separating said pilot signal component from the received radio signals,means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, andmeans (35) for establishing for said pilot signal component from said separating means a predetermined, nonzero, minimum, envelope value to prevent excessive bursts of gain-corrected information component during deep received signal fades.
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Accused Products
Abstract
Effects of multipath fading and Doppler frequency spread in a single sideband radio communication system are largely overcome by separating (17) from a received signal spectrum, a pilot frequency component including those effects and using that component to accomplish both phase (36) and gain (38) corrections on an information-containing frequency component. Signals essentially free of those effects are provided (10) for controlling necessary frequency translations in the receiver. One illustrative embodiment (FIG. 4) is conveniently arranged for facilitating diversity signal combining.
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Citations
34 Claims
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1. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, both components having said distortion effects therein as received, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, and means (35) for establishing for said pilot signal component from said separating means a predetermined, nonzero, minimum, envelope value to prevent excessive bursts of gain-corrected information component during deep received signal fades.
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2. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, said separating means including means (19-23) for extracting from said received signals a portion of the frequency spectrum thereof including a baseband portion representing said phase and gain distortion effects with respect to said pilot component, and means (28, 29) for translating said baseband portion to a predetermined nonbaseband level in the frequency spectrum, and means (38), responsive to an output of said translating means, for effecting forward gain correction of the information component of the received signals.
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3. In a single sideband radio receiver for radio signals including phase and Rayleigh fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, said separating means including a translating bandpass filter, and means (38), responsive to the pilot component, for effecting forward gain correction of at least said Rayleigh fading effects in the information component of the received signals.
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4. In a single sideband radio receiver for radio signals including phase and Rayleigh fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, means for separating said information component from said received signals by a translating bandpass filter, and means (38), responsive to the pilot component, for effecting forward gain correction of at least said Rayleigh fading effects in the information component of the received signals.
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5. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, said separating means including a translating bandpass filter, means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, and means (10), independent of received signal phase, for supplying predetermined control frequency signals to control said translating bandpass filter.
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7. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, said separating means including a translating bandpass filter, means (18) for separating said information component from said received signals by a translating bandpass filter, means (10), independent of received signal phase, for supplying signals of predetermined frequency to control said translating bandpass filters, and means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals.
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8. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, said separating means including a translating bandpass filter, means (18) for separating said information component from said received signals by a translating bandpass filter, means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, and means (26, 27) in said translating bandpass filter for said information component for matching signal propagation delays for said pilot component and said information component prior to application of said such components to said gain correcting means.
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9. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, said separating means including a translating bandpass filter, means (18) for separating said information component from said received signals by a translating bandpass filter, means for supplying control frequency reference signals to said translating bandpass filters, means for coupling data signals to said supplying means for specifying the frequencies of signals to be provided by said supplying means, and means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals.
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11. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, means separating said information component from said received signals by a translating bandpass filter, means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, and means (26, 27), included in said filter, for matching the signal delay of said pilot signal component and said information signal component prior to application of said components to said gain correcting means.
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14. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, means (36), responsive to the pilot signal component, for effecting phase correction of the information component, and said separating means comprises means (19-23) for extracting from said received signals a portion of the frequency spectrum thereof including a baseband portion representing said phase and gain distortion effects with respect to said pilot component, and means (28, 29) for translating said baseband portion to a predetermined nonbaseband level in the frequency spectrum for application to control said phase and gain correction effecting means.
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15. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, means (36), responsive to the pilot signal component, for effecting phase correction of the information component, and means (26, 27) for matching the signal delay of said pilot signal component and said information signal component prior to application of said components to said phase correcting means and to said gain correcting means.
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17. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, and means (36), responsive to the pilot signal component, for effecting phase correction of the information component, said phase correcting means comprising means (36) for frequency mixing a first input including an output of said separating means with a second input including at least said information component of said received signals to remove frequency components that are common to both of said mixing inputs, said mixing means also simultaneously translating said information component to a different frequency level.
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24. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
means (17), including a first translating bandpass filter, for separating said pilot signal component from the received radio signals, means (38), responsive to the pilot component, for effecting forward gain correction of the information component of the received signals, a second translating bandpass filter (18) for separating said information component from said received signals, means (10), independent of the signal phase of said received signals, for supplying predetermined control frequency signals to said translating bandpass filters, means (36), responsive to the pilot signal component, for effecting phase correction of the information component, said phase correcting means including frequency mixing means (36) having an input coupled to the output of said second translating bandpass filter, and signal limiting means (32) for coupling an output of said first translating bandpass filter to a futher input of said frequency mixing means and stripping substantially all amplitude variations from such output to leave signal zero crossing information for application to said mixing means, and said gain correcting means comprises means (33) for detecting amplitude envelope variations in the output of said first translating bandpass filter, means (39) for coupling an output of said envelope detecting means to compensate said received signals for relatively slow signal amplitude variations therein, a gain correcting circuit (38), means for further coupling said envelope detector output to an input of said gain correcting circuit, means (37) for coupling at least one sideband of said information component in the output of said mixing means to further input of said gain correcting circuit, and means (38) for interacting signals at said inputs thereof to cancel like amplitude variations in common phase prior to applying the net corrected signal to an output of said gain correcting circuit.
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30. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the signals including at least an information component and a pilot component, the improvement comprising
plural signal reception modules (47, 48), each including means (17) for separating said pilot signal component from the received radio signals, and means (36), responsive to the pilot component, for effecting phase correction of the information component, such phase correction means producing a phase corrected information component of said received signals, and means (52) for summing said phase corrected information components of said respective modules.
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31. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the receiver including nonlinear envelope detecting means (33), the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component from the received radio signals, means for applying the separated pilot component to said detecting means, means (38), responsive to the detected pilot component envelope, for effecting forward gain correction of the information component of the received signals, and means (26, 27) for matching the signal delay of said pilot signal component and said information signal component prior to application of said components to said gain correcting means.
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32. In a single sideband receiver for radio signals including amplitude and phase fluctuations, said signals including at least an information component and a pilot component, a method for substantially reducing said phase fluctuations in said information signals and including the steps of
frequency mixing to translate at least said pilot component to a first band and filtering that band to restrict the width thereof to substantially only said pilot component with its said phase fluctuations, frequency mixing said first band signals to translate them to a second band including a suppressed carrier frequency corresponding to said information component associated with a predetermined intermediate frequency band, amplitude limiting second band signals to remove said amplitude fluctuations, and frequency mixing said information component and the output of the limiting step to reduce substantially said phase fluctuations.
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34. In a single sideband radio receiver for radio signals including phase and fading distortion effects, the receiver including nonlinear envelope detecting means (33), the signals including at least an information component and a pilot component, the improvement comprising
means (17) for separating said pilot signal component, without significant information component energy, from the received radio signals, means for applying the separated pilot component to said detecting means, and means (38), responsive to the separated pilot component envelope, for effecting forward gain correction of the information component of the received signals, said effecting means including means (38) for dividing said information signal component by the amplitude envelope of said pilot component for cancelling corresponding amplitude variations common to both of said components.
Specification