Method and apparatus for signal processing using reference signals
First Claim
Patent Images
1. A method of processing signals comprising steps of:
- combining a spread spectrum reference signal with an input signal to be processed into a combined signal;
processing said combined signal to provide a processed combined signal;
deriving an intermediate signal dependent on said processed combined signal and Said input signal;
adjusting at least one of a phase and an amplitude of said intermediate signal in response to control signals to form an adjusted intermediate signal;
combining said adjusted intermediate signal with at least one of said combined signal and said processed combined signal to form a resultant signal; and
deriving said control signals from said resultant signal.
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Abstract
The invention provides methods and apparatus for substituting a reference spread spectrum signal for a pilot tone or providing a reference spread spectrum signal where no pilot tone has been used. The invention has particular relevance when a large number of input channels are required for a broad band linear amplifier and when an omni-directional antenna is required for a repeater which may be prone to instability.
63 Citations
30 Claims
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1. A method of processing signals comprising steps of:
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combining a spread spectrum reference signal with an input signal to be processed into a combined signal; processing said combined signal to provide a processed combined signal; deriving an intermediate signal dependent on said processed combined signal and Said input signal; adjusting at least one of a phase and an amplitude of said intermediate signal in response to control signals to form an adjusted intermediate signal; combining said adjusted intermediate signal with at least one of said combined signal and said processed combined signal to form a resultant signal; and deriving said control signals from said resultant signal. - View Dependent Claims (2, 3, 4)
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5. An apparatus for processing signals comprising:
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means for combining a spread spectrum reference signal with an input signal to be processed into a combined signal; means for processing said combined signal to provide a processed combined signal; means for deriving an intermediate signal dependent on said processed combined signal and said input signal; means for adjusting at least one of a phase and an amplitude of said intermediate signal in response to control signals to form an adjusted intermediate signal; means for combining said adjusted intermediate signal with at least one of said combined signal and said processed combined signal to form a resultant signal; and means for deriving said control signals from said resultant signal.
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6. A method of processing signals comprising steps of:
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combining a spread spectrum reference signal having a predetermined characteristic with input signals which are not spread spectrum modulated to form a combined signal; processing said combined signal to provide a processed combined signal; further processing said processed combined signal; and extracting an extracted signal representative of said characteristic of said spread spectrum reference signal from said processed combined signal and said input signal to control, at least partially, said further processing of said processed combined signal. - View Dependent Claims (8, 9, 10)
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7. A method of processing signals comprising steps of:
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combining a spread spectrum reference signal having a predetermined characteristic with input signals which are not spread spectrum modulated to form a combined signal; processing said combined signal to provide a processed combined signal, said step of processing said combined signal comprising amplification; further processing said processed combined signal; extracting an extracted signal representative of said characteristic of said spread spectrum reference signal from said processed combined signal to control, at least partially, said further processing of said processed combined signal deriving an error signal representative of distortion introduced by said amplification; subtracting said error signal from at least one of said processed combined signal and said further processed processed combined signal; and using said extracted signal to control an amplitude and a phase of said processed combined signal relative to said error signal before said error signal is subtracted from said processed combined signal.
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11. An apparatus for processing signals comprising:
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means for combining a spread spectrum reference signal having a predetermined characteristic with input signals which are not spread spectrum modulated to form a combined signal; means for processing said combined signal to provide a processed combined signal; means for further processing said processed combined signal; and means for extracting an extracted signal representative of said characteristic of said spread spectrum reference signal from said processed combined signal and said input signal to control, at least partially, said further processing of said processed combined signal.
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12. A broadband linear amplifier circuit comprising:
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amplifier means having an input and an output; first difference means for deriving an error signal representative of distortion introduced by said amplifier means from signals representative of input signals applied to said input of said amplifier means, said first difference means deriving a difference between a first signal representative of said input signal applied to said amplifier means and a second signal representative of said output signals from said output of said amplifier means; second difference means for subtracting a signal representative of said error signal from output signals representative of said output of said amplifier means to provide a low distortion output signal; adjustment means responsive to control signals for adjusting a phase and an amplitude of signals applied to said first difference means simultaneously with a phase and an amplitude of signals applied to said second difference means; means for generating a spread spectrum reference signal and for combining said spread spectrum reference signal with at least one of said input signals and said signals representative of said input signals; and control means for generating said control signals from both an amount of said spread spectrum reference signal remaining in said low distortion output signal and a signal representative of one of said spread spectrum reference signal and said error signal. - View Dependent Claims (13, 14, 16, 17, 18, 20, 21)
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15. A broadband linear amplifier circuit comprising:
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amplifier means having an input and an output; first difference means for deriving an error signal representative of distortion introduced by said amplifier means from signals representative of input signals applied to said input of said amplifier means; second difference means for subtracting a signal representative of said error signal from output signals representative of said output of said amplifier means to provide a low distortion output signal; adjustment means responsive to control signals for adjusting a relative phase and an amplitude of signals applied to at least one of said first difference means and said second difference means; means for generating a spread spectrum reference signal and for combining said spread spectrum reference signal with at least one of said input signals and said signals representative of said input signals, said means for generating said spread spectrum reference signal comprising; means for providing a signal at a center frequency of a band of frequencies to be amplified, means for providing a series of pulses having a bandwidth equal to that of said band of frequencies, said pulses having a significance according to a pseudo-random repeatable sequence, and means for combining said signal at said center frequency with said series of pulses to provide said spread spectrum reference signal; and control means for generating said control signals from both an amount of said spread spectrum reference signal remaining in said low distortion output signal and a signal representative of one of said spread spectrum reference signal and said error signal.
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19. A broadband linear amplifier circuit comprising:
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amplifier means having an input and an output; first difference means for deriving an error signal representative of distortion introduced by said amplifier means from signals representative of input signals applied to said input of said amplifier means, said first difference means deriving a difference between a first signal representative of an input signal applied to said amplifier means and a second signal representative of an output signal from said output of said amplifier means; second difference means for subtracting a signal representative of said error signal from output signals representative of said output of said amplifier means to provide a low distortion output signal; adjustment means responsive to control signals for adjusting a relative phase and an amplitude of signals applied to at least one of said first difference means and said second difference means; means for generating a spread spectrum reference signal and for combining said spread spectrum reference signal with at least one of said input signals and said signals representative of said input signals, said means for generating said spread spectrum reference signal comprising; means for providing a signal at a center frequency of a band of frequencies to be amplified, means for providing a series of pulses having a bandwidth equal to that of said band of frequencies, said pulses having a significance according to a pseudo-random repeatable sequence and means for combining said signal at said center frequency with said series of pulses to provide said spread spectrum reference signal; and control means for generating said control signals from both an amount of said spread spectrum reference signal remaining in said low distortion output signal and a signal representative of one of said spread spectrum reference signal and said error signal.
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22. A method of broad band linear amplification comprising steps of:
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amplifying input signals to form amplified output signals; deriving an error signal representative of distortion introduced by said step of amplifying input signals; subtracting said error signal from said amplified output signals to provide low distortion signals; simultaneously adjusting a relative phase and an amplitude of at least one of signals used in deriving said error signal, said input signals, and said amplified output signals, in response to control signals; generating a spread spectrum reference signal; combining said spread spectrum reference signal with said input signals; and generating said control signals from both an amount of said spread spectrum reference signal remaining in said low distortion signals and a signal representative of at least one of said spread spectrum reference signal and said error signal.
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23. A radio repeater comprising:
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an amplifier coupled between receive and transmit points; means for deriving a cancellation signal representative of an output signal from said amplifier; means for adjusting an amplitude and a phase of said cancellation signal in response to control signals; difference means for subtracting said cancellation signal from signals received at said receive point; means for combining signals at said receive point with a spread spectrum reference signal; and means for deriving said control signals from at least one of said spread spectrum reference signal and said signals at said transmit point. - View Dependent Claims (24)
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25. A method of processing a signal comprising the steps of:
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combining a spread spectrum reference signal with an input signal to generate a combined signal; processing said combined signal to provide a processed combined signal; extracting an intermediate signal dependent upon said processed combined signal; firstly deriving a first set of control signals; adjusting at least one of an amplitude and a phase of said intermediate signal in response to said first set of control signals to provide an adjusted intermediate signal; combining said adjusted intermediate signal with at least one of said combined signal and said processed combined signal to provide a resultant signal; secondly deriving a second set of control signals; adjusting at least one of an amplitude and a phase of said resultant signal in response to said second set of control signals to provide an adjusted resultant signal; wherein said first set of control signals and said second set of control signals enable said phase and said amplitude of said intermediate signal to be adjusted concurrently with said phase and said amplitude of said resultant signal. - View Dependent Claims (26)
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27. A broadband linear amplifier circuit comprising:
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amplifier means having an input and an output; first difference means for deriving an error signal representative of distortion introduced by said amplifier means from signals representative of input signals applied to said input of said amplifier means; second difference means for subtracting a signal representative of said error signal from output signals representative of said output of said amplifier means to provide a low distortion output signal; adjustment means responsive to control signals for adjusting a relative phase and an amplitude of signals applied to at least one of said first difference means and said second difference means; means for adding simulated distortion to at least one of said input signals and said signals representative of said input signals; and control means for generating said control signals from both an amount of said simulated distortion remaining in said low distortion output signal and a signal representative of one of said simulated distortion and said error signal. - View Dependent Claims (28)
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29. A method of processing a signal comprising the steps of:
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combining a spread spectrum reference signal with an input signal to generate a combined signal; processing said combined signal to provide a processed combined signal; extracting an intermediate signal dependent upon said processed combined signal; firstly deriving a first set of control signals; adjusting at least one of an amplitude and a phase of said intermediate signal in response to said first set of control signals to provide an adjusted intermediate signal; combining said adjusted intermediate signal with at least one of said combined signal and said processed combined signal to provide a resultant signal; secondly deriving a second set of control signals; adjusting at least one of an amplitude and a phase of at least one of said adjusted intermediate signal, said combined signal, and said processed combined signal in response to said second set of control signals to provide an adjusted resultant signal; wherein said first set of control signals and said second set of control signals enable said phase and said amplitude of said intermediate signal to be adjusted concurrently with said phase and said amplitude of said at least one of said adjusted intermediate signal, said combined signal, and said processed combined signal.
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30. A broadband linear amplifier circuit comprising:
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amplifier means having an input and an output, said amplifier means comprising; an amplifier, and means for correcting distortion introduced by said amplifier by generating an error signal and subtracting said error signal from an output signal from said amplifier; first difference means for deriving an error signal representative of distortion introduced by said amplifier means from signals representative of input signals applied to said input of said amplifier means, said first difference means deriving a difference between a first signal representative of said input signal applied to said amplifier means and a second signal representative of said output signals from said output of said amplifier means; second difference means for subtracting a signal representative of said error signal from output signals representative of said output of said amplifier means to provide a low distortion output signal; adjustment means responsive to control signals for adjusting a relative phase and an amplitude of signals applied to at least one of said first difference means and said second difference means; means for generating a spread spectrum reference signal and for combining said spread spectrum reference signal with at least one of said input signals and said signals representative of said input signals, said means for generating said spread spectrum reference signal comprising; means for providing a signal at a center frequency of a band of frequencies to be amplified, means for providing a series of pulses having a bandwidth equal to that of said band of frequencies, said pulses having a significance according to a pseudo-random repeatable sequence, and means for combining said signal at said center frequency with said series of pulses to provide said spread spectrum reference signal; control means for generating said control signals from both an amount of said spread spectrum reference signal remaining in said low distortion output signal and a signal representative of one of said spread spectrum reference signal and said error signal.
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Specification