Phase-difference-corresponding-value measurement device, gain imbalance measurement device, method, program, and recording medium

A gain imbalance measurement device which receives a demodulated signal from a quadrature demodulator for receiving a modulated signal output by a quadrature modulator, and applying quadrature demodulation to the received signal, and measures a gain imbalance which is a ratio between the amplitude of a I component of the modulated signal and the amplitude of an Q component, wherein an original I signal and an original Q signal are fed to the quadrature modulator at a predetermined time point, the original I signal having a frequency of the original Q signal at the predetermined time point, and the original Q signal having a frequency of the original I signal at the predetermined time point are fed to the quadrature modulator after the predetermined time point, the quadrature modulator applies the quadrature modulation to the original I signal and the original Q signal having frequencies different from each other, the frequency of the original I signal is referred to as I frequency, a frequency obtained by inverting the sign of the frequency of the original I signal is referred to as opposite-sign I frequency, the frequency of the original Q signal is referred to as Q frequency, a frequency obtained by inverting the sign of the frequency of the original Q signal is referred to as opposite-sign Q frequency, the gain imbalance measurement device comprising:

• an I-frequency-amplitude deriving unit that derives an amplitude of a component of the I frequency of the demodulated signal;
• an opposite-sign I-frequency-amplitude deriving unit that derives an amplitude of a component of the opposite-sign I frequency of the demodulated signal;
• a Q-frequency-amplitude deriving unit that derives an amplitude of a component of the Q frequency of the demodulated signal;
• an opposite-sign Q-frequency-amplitude deriving unit that derives an amplitude of a component of the opposite-sign Q frequency of the demodulated signal;
• a first amplitude ratio deriving unit that derives a ratio between the derived result of the I-frequency-amplitude deriving unit and the derived result of the Q-frequency-amplitude deriving unit for the respective frequencies;
• a second amplitude ratio deriving unit that derives a ratio between the derived result of the opposite-sign I-frequency-amplitude deriving unit and the derived result of the opposite-sign Q-frequency-amplitude deriving unit for the respective frequencies;
• and
• an averaging unit that derives the gain imbalance based on an average of the derived result of the first amplitude ratio deriving unit and the derived result of the second amplitude ratio deriving unit.

A phase-difference-corresponding-value measurement method of receiving a demodulated signal from a quadrature demodulator for receiving a modulated signal output by a quadrature modulator, and applying quadrature demodulation to the received signal, and measuring a phase-difference corresponding value corresponding to a phase difference between an I component and a Q component of the modulated signal, wherein the quadrature modulator applies the quadrature modulation to an original I signal and an original Q signal having frequencies different from each other, the frequency of the original I signal is referred to as I frequency, a frequency obtained by inverting the sign of the frequency of the original I signal is referred to as opposite-sign I frequency, the frequency of the original Q signal is referred to as Q frequency, a frequency obtained by inverting the sign of the frequency of the original Q signal is referred to as opposite-sign Q frequency, the phase-difference-corresponding-value measurement method comprising:

• deriving the phase of a component of the I frequency of the demodulated signal;
• deriving the phase of a component of the opposite-sign I frequency of the demodulated signal;
• deriving the phase of a component of the Q frequency of the demodulated signal;
• deriving the phase of a component of the opposite-sign Q frequency of the demodulated signal;
• deriving a first phase-difference corresponding value corresponding to a difference between the derived result of the deriving of the I-frequency-phase and the derived result of the deriving of the Q-frequency-phase;
• deriving a second phase-difference corresponding value corresponding to a difference between the derived result of the deriving of the opposite-sign I-frequency-phase and the derived result of the deriving of the opposite-sign Q-frequency-phase;
• and
• deriving the average of the phase-difference corresponding value based on an average of the first phase-difference corresponding value and the second phase-difference corresponding value.

A gain imbalance measurement method of receiving a demodulated signal from a quadrature demodulator for receiving a modulated signal output by a quadrature modulator, and applying quadrature demodulation to the received signal, and measuring a gain imbalance which is a ratio between the amplitude of a I component of the modulated signal and the amplitude of an Q component, wherein an original I signal and an original Q signal are fed to the quadrature modulator at a predetermined time point, the original I signal having a frequency of the original Q signal at the predetermined time point, and the original Q signal having a frequency of the original I signal at the predetermined time point are fed to the quadrature modulator after the predetermined time point, the quadrature modulator applies the quadrature modulation to the original I signal and the original Q signal having frequencies different from each other, the frequency of the original I signal is referred to as I frequency, a frequency obtained by inverting the sign of the frequency of the original I signal is referred to as opposite-sign I frequency, the frequency of the original Q signal is referred to as Q frequency, a frequency obtained by inverting the sign of the frequency of the original Q signal is referred to as opposite-sign Q frequency, the gain imbalance measurement method comprising:

• deriving an amplitude of a component of the I frequency of the demodulated signal;
• deriving an amplitude of a component of the opposite-sign I frequency of the demodulated signal;
• deriving an amplitude of a component of the Q frequency of the demodulated signal;
• deriving an amplitude of a component of the opposite-sign Q frequency of the demodulated signal;
• a deriving a first amplitude ratio between the derived result of the deriving of the I-frequency-amplitude and the derived result of the deriving of the Q-frequency-amplitude for the respective frequencies;
• deriving a second amplitude ratio between the derived result of the deriving of the opposite-sign I-frequency-amplitude and the derived result of the deriving of the opposite-sign Q-frequency-amplitude for the respective frequencies;
• and
• deriving the average of the gain imbalance based on an average of the derived result of the deriving of the first amplitude ratio and the derived result of the deriving of the second amplitude ratio.

A computer-readable medium having a program of instructions for execution by a computer to perform a phase-difference-corresponding-value measurement process of receiving a demodulated signal from a quadrature demodulator for receiving a modulated signal output by a quadrature modulator, and applying quadrature demodulation to the received signal, and measuring a phase-difference corresponding value corresponding to a phase difference between an I component and a Q component of the modulated signal, wherein the quadrature modulator applies the quadrature modulation to an original I signal and an original Q signal having frequencies different from each other, the frequency of the original I signal is referred to as I frequency, a frequency obtained by inverting the sign of the frequency of the original I signal is referred to as opposite-sign I frequency, the frequency of the original Q signal is referred to as Q frequency, a frequency obtained by inverting the sign of the frequency of the original Q signal is referred to as opposite-sign Q frequency, the phase-difference-corresponding-value measurement process comprising:

• deriving the phase of a component of the I frequency of the demodulated signal;
• deriving the phase of a component of the opposite-sign I frequency of the demodulated signal;
• deriving the phase of a component of the Q frequency of the demodulated signal;
• deriving the phase of a component of the opposite-sign Q frequency of the demodulated signal;
• deriving a first phase-difference corresponding value corresponding to a difference between the derived result of the deriving of the I-frequency-phase and the derived result of the deriving of the Q-frequency-phase;
• deriving a second phase-difference corresponding value corresponding to a difference between the derived result of the deriving of the opposite-sign I-frequency-phase and the derived result of the deriving of the opposite-sign Q-frequency-phase;
• and
• deriving the average of the phase-difference corresponding value based on an average of the first phase-difference corresponding value and the second phase-difference corresponding value.

A computer-readable medium having a program of instructions for execution by a computer to perform a gain imbalance measurement process of receiving a demodulated signal from a quadrature demodulator for receiving a modulated signal output by a quadrature modulator, and applying quadrature demodulation to the received signal, and measuring a gain imbalance which is a ratio between the amplitude of a I component of the modulated signal and the amplitude of an Q component, wherein an original I signal and an original Q signal are fed to the quadrature modulator at a predetermined time point, the original I signal having a frequency of the original Q signal at the predetermined time point, and the original Q signal having a frequency of the original I signal at the predetermined time point are fed to the quadrature modulator after the predetermined time point, the quadrature modulator applies the quadrature modulation to the original I signal and the original Q signal having frequencies different from each other, the frequency of the original I signal is referred to as I frequency, a frequency obtained by inverting the sign of the frequency of the original I signal is referred to as opposite-sign I frequency, the frequency of the original Q signal is referred to as Q frequency, a frequency obtained by inverting the sign of the frequency of the original Q signal is referred to as opposite-sign Q frequency, the gain imbalance measurement process comprising:

• deriving an amplitude of a component of the I frequency of the demodulated signal;
• deriving an amplitude of a component of the opposite-sign I frequency of the demodulated signal;
• deriving an amplitude of a component of the Q frequency of the demodulated signal;
• deriving an amplitude of a component of the opposite-sign Q frequency of the demodulated signal;
• deriving a first amplitude ratio between the derived result of the deriving of the I-frequency-amplitude and the derived result of the deriving of the Q-frequency-amplitude for the respective frequencies;
• deriving a second amplitude ratio between the derived result of the deriving of the opposite-sign I-frequency-amplitude and the derived result of the deriving of the opposite-sign Q-frequency-amplitude for the respective frequencies;
• and
• deriving the average of the gain imbalance based on an average of the derived result of the deriving of the first amplitude ratio and the derived result of the deriving of the second amplitude ratio.