Apparatus and method for multicarrier modulation and demodulation
First Claim
1. A method for multicarrier signal modulation, comprising the steps of:
- maintaining substantially identical gain and group delays between transmit in-phase (I) and transmit quadrature-phase (Q) paths, comprising;
receiving a transmit I digital baseband signal and a transmit Q digital baseband signal of a first multicarrier communication signal;
digitally constructing a digital transmit intermediate frequency (IF) signal from the transmit I and Q digital baseband signals including bandpass sampling, wherein bin-by-bin amplitude and delay resulting in the I path is substantially equal to bin-by-bin amplitude and delay resulting in the Q path; and
converting the digital transmit IF signal to an analog transmit IF signal.
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Abstract
The present invention provides a method and apparatus for signal processing for signal modulation and demodulation. In signal processing the present invention maintains substantially identical gain and group delays between transmit in-phase (I) and transmit quadrature-phase (Q) paths by receiving a digital transmit I baseband signal and a digital transmit Q baseband signal of a first multicarrier communication signal. A digital transmit IF signal is digitally constructed from the transmit I and Q digital baseband signals including bandpass sampling and the digital transmit IF signal is converted to an analog transmit IF signal. The present invention additionally maintains substantially identical gain and group delays between receive I and Q paths.
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Citations
31 Claims
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1. A method for multicarrier signal modulation, comprising the steps of:
maintaining substantially identical gain and group delays between transmit in-phase (I) and transmit quadrature-phase (Q) paths, comprising;
receiving a transmit I digital baseband signal and a transmit Q digital baseband signal of a first multicarrier communication signal;
digitally constructing a digital transmit intermediate frequency (IF) signal from the transmit I and Q digital baseband signals including bandpass sampling, wherein bin-by-bin amplitude and delay resulting in the I path is substantially equal to bin-by-bin amplitude and delay resulting in the Q path; and
converting the digital transmit IF signal to an analog transmit IF signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for multicarrier signal conditioning for communication, comprising the steps of:
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receiving an analog receive intermediate frequency (IF) signal of a first multicarrier communication signal;
converting the analog receive IF signal to a digital receive IF signal;
commutating the digital receive IF signal producing a digital receive I bandpass signal and a digital receive Q bandpass signals;
interpolating the digital receive Q bandpass signal;
interpolating the digital receive I bandpass signal; and
generating digital receive I baseband signal and a digital receive Q baseband signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for multicarrier signal processing, comprising:
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a first interpolator coupled to receive digital bandpass in-phase (I) signal of a multicarrier signal, and configured to adjust a delay of digital bandpass I signal;
a second interpolator coupled to receive digital bandpass quadrature-phase (Q) signal of a multicarrier signal, and configured to adjust a delay of digital bandpass Q signal;
a transmit signal construction unit coupled with the first and second interpolators, and configured to construct a digital IF transmit signal from the adjusted digital bandpass I and Q signals; and
a digital-to-analog converter coupled with the transmit signal construction unit to receive the digital IF transmit signal, and configured to convert the digital IF transmit signal to an analog IF transmit signal. - View Dependent Claims (21, 22, 23, 24)
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25. An apparatus for multicarrier signal processing, comprising:
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a analog-to-digital converter configured to receive an analog IF receive signal of a multicarrier signal and to convert the analog IF receive signal to a digital IF receive signal;
a receive signal decomposition unit coupled with the analog-to-digital converter, and configured to decompose the digital IF receive signal into a digital IF in-phase (I) receive signal and digital IF quadrature-phase (Q) receive signal;
a first interpolator coupled with the decomposition unit to receive the digital I receive signal, and configured to adjust a delay of digital I receive signal producing digital bandpass I receive signal; and
a second interpolator coupled with the decomposition unit to receive the digital Q receive signal, and configured to adjust a delay of digital Q receive signal producing digital bandpass Q receive signal. - View Dependent Claims (26, 27)
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28. A method for multicarrier signal modulation, comprising the steps of:
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determining a frequency error from an in-phase (I) signal and a quadrature-phase (Q) signal; and
implementing time base adjustments of the I- and Q-signals based on the RF frequency errors. - View Dependent Claims (29, 30, 31)
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Specification