Method and apparatus for multi-phase component downconversion
First Claim
1. A downconverter, comprising:
- an analog-to-digital converter operatively coupled to receive an intermediate frequency signal and to provide a digital signal at a sampling rate;
a Hilbert transformation network operatively coupled to said analog-to-digital converter to provide a passband quadrature component of the digital signal;
a delay element operatively coupled to said analog-to-digital converter to provide a passband in-phase component of the digital signal; and
a digital translator operatively coupled to said Hilbert transformation network and said delay element to alter the passband quadrature and passband in-phase components based on at least one predetermined pattern to provide a baseband quadrature signal and a baseband in-phase signal.
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Abstract
The present invention provides a downconverter method and apparatus for downconverting a multiphase modulated signal. The downconverter can be implemented in a multi-phase receiver such as a quadrature receiver. An analog-to-digital converter (103) converts an intermediate frequency signal to a digital signal at a sampling rate. A Hilbert transformation filter (104) and a delay element (105) connected in parallel provide respective passband quadrature and in-phase components of the digital signal. A digital translator (107) alters the passband quadrature and in-phase components based on a predetermined pattern to provide a baseband quadrature signal and a baseband in-phase signal. The digital translator (107) can be a pseudorandom sequence demodulator for demodulating a code division multiple access (CDMA) signal. Various types of DC estimation can also be provided in addition to automatic gain control.
160 Citations
48 Claims
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1. A downconverter, comprising:
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an analog-to-digital converter operatively coupled to receive an intermediate frequency signal and to provide a digital signal at a sampling rate; a Hilbert transformation network operatively coupled to said analog-to-digital converter to provide a passband quadrature component of the digital signal; a delay element operatively coupled to said analog-to-digital converter to provide a passband in-phase component of the digital signal; and a digital translator operatively coupled to said Hilbert transformation network and said delay element to alter the passband quadrature and passband in-phase components based on at least one predetermined pattern to provide a baseband quadrature signal and a baseband in-phase signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A receiver, comprising:
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an analog-to-digital converter operatively coupled to sample an intermediate frequency signal at a sampling rate and provide a digital signal; a first transformation network operatively coupled to said analog-to-digital converter to provide a passband quadrature component of the digital signal; a second transformation network operatively coupled to said analog-to-digital converter to provide a passband in-phase component of the digital signal; a digital translator operatively coupled to said first transformation network and said second transformation network to alter the passband quadrature and passband in-phase components based on at least one predetermined pattern to provide a baseband quadrature signal and a baseband in-phase signal; and a DC estimator operatively coupled to substantially eliminate DC from the baseband quadrature signal and the baseband in-phase signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A CDMA receiver, comprising:
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analog-to-digital converting means for sampling an IF signal at a sampling rate to provide a digital signal; transformation means for transforming the digital signal to provide a passband quadrature component of the digital signal and a passband in-phase component of the digital signal; and translator means for altering and despreading the passband quadrature and passband in-phase components based on both a predetermined pattern and a pseudorandom sequence to provide a baseband quadrature signal and a baseband in-phase signal.
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23. A method for down-converting a signal, the method comprising the steps of:
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(a) sampling an intermediate frequency signal at a sampling rate to produce a digital signal; (b) transforming the digital signal to produce a passband quadrature component; (c) delaying the digital signal to produce a passband in-phase component; and (d) altering the passband quadrature and passband in-phase components based on at least one predetermined pattern to provide a baseband quadrature signal and a baseband in-phase signal. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A downconverter, comprising:
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an analog-to-digital converter operatively coupled to receive an intermediate frequency signal and to provide a digital signal at a sampling rate; a Hilbert transformation network operatively coupled to said analog-to-digital converter to provide a passband quadrature component of the digital signal; a delay element operatively coupled to said analog-to-digital converter to provide a passband in-phase component of the digital signal; and a digital translator operatively coupled to said Hilbert transformation network and said delay element to alter the passband quadrature and passband in-phase components based on at least one time variant predetermined pattern to provide a baseband quadrature signal and a baseband in-phase signal. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
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41. A CDMA receiver, comprising:
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analog-to-digital converting means for sampling an IF signal at a sampling rate to provide a digital signal; transformation means for transforming the digital signal to provide a passband quadrature component of the digital signal and a passband in-phase component of the digital signal; and translator means for altering and despreading the passband quadrature and passband in-phase components based on both a time variant predetermined pattern and a pseudorandom sequence to provide a baseband quadrature signal and a baseband in-phase signal.
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42. A method for down-converting a signal, the method comprising the steps of:
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(a) sampling an intermediate frequency signal at a sampling rate to produce a digital signal; (b) transforming the digital signal to produce a passband quadrature component; (c) delaying the digital signal to produce a passband in-phase component; and (d) altering the passband quadrature and passband in-phase components based on at least one time variant predetermined pattern to provide a baseband quadrature signal and a baseband in-phase signal. - View Dependent Claims (43, 44, 45, 46, 47, 48)
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Specification