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US 8,315,338 B2Granted
Orthogonality detector, and quadrature demodulator and sampling quadrature demodulator using detector thereof
AssigneeHitachi, Ltd.
InventorsShigenori Hayase, Kazuyuki Hori
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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.
Claims7
A sampling quadrature demodulator comprising:
- a sampling quadrature demodulation circuit section which samples in-phase components and quadrature components of an input signal at 1/n of the carrier frequency of the input signal, and outputs, via an output terminal, the sampled in-phase and quadrature components as the sampled in-phase digital signals and quadrature digital signals;
- and
- a group delay difference compensator connected to the output terminal of the sampling quadrature demodulation circuit section, and which differentiates the delay difference between the in-phase digital signals and the quadrature digital signals, and compensates the group delay difference between the demodulated in-phase components and quadrature components,
- wherein sampling timing between the in-phase and quadrature components differs by ¼ of a sample period, and
- wherein the group delay difference compensator is configured to compensate for the sampling timing difference between the in-phase and quadrature components of ¼ the sample period.
2 more elements
Dependencies are inferred from the claim text.