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US 2006/0056546 A1Published application
Orthogonality detector, and quadrature demodulator and sampling quadrature demodulator using detector thereof
AssigneeHitachi, Ltd.
InventorsShigenori Hayase, Kazuyuki Hori
Life of this patent
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Abstract
To detect phase mismatches between in-phase and quadrature signals of a quadrature demodulator. The phase mismatches can be detected using the signals obtained by removing high frequency components of output of a multiplier by a low pass filter, the output being the product of the in-phase signals of which low frequency components are removed by a first high pass filter by the quadrature signals of which low frequency components are removed by a second high pass filter.
Claims22
An orthogonality detector,
- wherein the orthogonality detector is structured so as to calculate covariance of two input signals and detect orthogonality between the two signals from the calculated. covariance.
An orthogonality detector, comprising:
- a first high pass filter for removing low frequency components of a first input signal;
- a second high pass filter for removing low frequency components of a second input signal;
- a multiplier for multiplying the respective outputs of the first and second high pass filters each other;
- and
- a low pass filter for removing high frequency components from the output of the multiplier,
- wherein the orthogonality between the first and second signals is detected based on the outputs of the low pass filter.
3 more elements
A quadrature demodulator, comprising:
- a quadrature demodulation circuit section;
- and
- an orthogonality detector into which outputs of the quadrature demodulation circuit section are input, further comprising a circuit for compensating the phase mismatch between in-phase components and quadrature components from outputs of the quadrature demodulation circuit section based on the outputs of the orthogonality detector,
- wherein the orthogonality detector, comprising:
- a first high pass filter for removing low frequency components of in-phase components of the signal input from the quadrature demodulation circuit section,
- a second high pass filter for removing low frequency components of quadrature components of the signal input from the quadrature demodulation circuit section,
- a multiplier for multiplying the outputs of the first and second high pass filters each other, and
- a low pass filter for removing high frequency components from the output of the multiplier,
- detects the orthogonality between the in-phase and quadrature components of the signals input from the quadrature demodulation circuit section based on the output of the low pass filter, and
- makes the output of the quadrature demodulation circuit section of which the orthogonality error is compensated as output of the quadrature demodulator.
7 more elements
A sampling quadrature demodulator,
- wherein the sampling quadrature demodulator comprises:
- a sampling quadrature demodulation circuit section sampling input signals at 1/n of the carrier frequency of the input signal, synchronizing the timing between the in-phase components and quadrature components of the sampled input signal, and outputting generally synchronized in-phase digital signals and quadrature digital signals;
- and
- a group delay difference compensator being connected to the output terminal of the sampling quadrature demodulation circuit section, differentiating the delay difference between the in-phase digital signals and the quadrature digital signals, and compensating the group delay difference between the demodulated in-phase components and quadrature components.
1 more element
Dependencies are inferred from the claim text.