Amplitude error compensating device and quadrature skew error compensating device

An amplitude error compensating device comprising:

• an amplitude correcting section for performing amplitude correction with respect to an in-phase component and a quadrature component of a complex signal obtained by quadrature demodulation, based on amplitude error information, and outputting a resultant amplitude-corrected complex signal;
• and
• an amplitude error detecting section for obtaining the amplitude error information, depending on amplitudes of an in-phase component and a quadrature component of the amplitude-corrected complex signal,
• wherein the amplitude error detecting section comprises:
• a first power calculating section for obtaining a power of the amplitude-corrected complex signal;
• a second power calculating section for obtaining a power of the complex signal obtained by quadrature demodulation;
• an averaging section for obtaining an average value of the power obtained by the second power calculating section, and outputting the average value as an average power;
• a subtractor for obtaining a difference between the power obtained by the first power calculating section and the average power, and outputting the difference as a power difference;
• an area determining section for determining to which of a plurality of areas on an IQ plane a signal point of the amplitude-corrected complex signal belongs, and outputting the result as an area determination signal;
• a sign determining section for outputting the power difference or the power difference whose sign has been inverted, in accordance with the area determination signal;
• and
• a smoothing section for smoothing an output of the sign determining section, and outputting the result as the amplitude error information.

A quadrature skew error compensating device comprising:

• a quadrature skew correcting section for performing quadrature skew correction with respect to a complex signal obtained by quadrature demodulation, based on quadrature skew error information, and outputting a resultant quadrature skew-corrected complex signal;
• and
• a quadrature skew error detecting section for obtaining a quadrature skew error between an in-phase component and a quadrature component of the quadrature skew-corrected complex signal, and outputting the quadrature skew error as the quadrature skew error information,
• wherein the quadrature skew error detecting section comprises:
• a power calculating section for obtaining a power of the quadrature skew-corrected complex signal;
• a quadrant determining section for determining to which of quadrants on an IQ plane a signal point of the quadrature skew-corrected complex signal belongs, and outputting the result as a quadrant determination signal;
• a sign determining section for outputting a value of the power or the power whose sign has been inverted, as a power error, in accordance with the quadrant determination signal;
• a rotation detecting section for detecting a rotation of the signal point of the quadrature skew-corrected complex signal, and outputting the result as a rotation detect signal;
• an error information control section for outputting the power error when the rotation detect signal indicates that the rotation of the signal point has been detected, and 0 when the rotation detect signal indicates that the rotation of the signal point has not been detected;
• and
• a smoothing section for smoothing an output of the error information control section, and outputting the result as the quadrature skew error information.

A quadrature skew error compensating device comprising:

• a quadrature skew correcting section for performing quadrature skew correction with respect to a complex signal obtained by quadrature demodulation, based on quadrature skew error information, and outputting a resultant quadrature skew-corrected complex signal;
• and
• a quadrature skew error detecting section for obtaining a quadrature skew error between an in-phase component and a quadrature component of the quadrature skew-corrected complex signal, and outputting the quadrature skew error as the quadrature skew error information,
• wherein the quadrature skew error detecting section comprises:
• a multiplier for multiplying the in-phase component and the quadrature component of the quadrature skew-corrected complex signal, and outputting the result;
• and
• a smoothing section for smoothing the result of the multiplication by the multiplier, and outputting the result as the quadrature skew error information.

A quadrature skew error compensating device comprising:

• a quadrature skew correcting section for performing quadrature skew correction with respect to a complex signal obtained by quadrature demodulation, based on quadrature skew error information, and outputting a resultant quadrature skew-corrected complex signal;
• and
• a quadrature skew error detecting section for obtaining a quadrature skew error between an in-phase component and a quadrature component of the quadrature skew-corrected complex signal, and outputting the quadrature skew error as the quadrature skew error information,
• wherein the quadrature skew error detecting section comprises:
• a first power calculating section for obtaining a power of the quadrature skew-corrected complex signal;
• a second power calculating section for obtaining a power of the complex signal obtained by the quadrature demodulation;
• an averaging section for obtaining an average value of the power obtained in the second power calculating section, and outputting the average value as an average power;
• a subtractor for obtaining a difference between the power calculated by the first power calculating section and the average power, and outputting the difference as a power difference;
• a quadrant determining section for determining to which of quadrants on an IQ plane a signal point of the quadrature skew-corrected complex signal belongs, and outputting the result as a quadrant determination signal;
• a sign determining section for outputting a value of the power difference or the power difference whose sign has been inverted, as a power error, in accordance with the quadrant determination signal;
• and
• a smoothing section for smoothing an output of the sign determining section, and outputting the result as the quadrature skew error information.

An amplitude/quadrature skew error compensating device comprising:

• an amplitude correcting section for performing amplitude correction with respect to an in-phase component and a quadrature component of a complex signal obtained by quadrature demodulation, based on amplitude error information, and outputting a resultant amplitude-corrected complex signal;
• an amplitude error detecting section for obtaining the amplitude error information, depending on amplitudes of an in-phase component and a quadrature component of the amplitude-corrected complex signal;
• a quadrature skew correcting section for performing quadrature skew correction with respect to the amplitude-corrected complex signal, based on quadrature skew error information, and outputting a resultant quadrature skew-corrected complex signal;
• and
• a quadrature skew error detecting section for obtaining a quadrature skew error between an in-phase component and a quadrature component of the quadrature skew-corrected complex signal, and outputting the quadrature skew error as the quadrature skew error information.