Phase shift precision calibration circuitry, vector sum phase shifter, and wireless communication device

:

• A vector sum phase shifter comprising:
• a vector summed part including
• an orthogonal signal generator to generate, from an input signal, a first signal and a second signal which are orthogonal to each other,
• a first variable gain amplifier to amplify the first signal generated by the orthogonal signal generator,
• a second variable gain amplifier to amplify the second signal generated by the orthogonal signal generator, and
• a signal combiner to combine the first signal amplified by the first variable gain amplifier and the second signal amplified by the second variable gain amplifier and output a combined signal of the first signal and the second signal;
• a table memory to store a relation between a control code corresponding to a phase shift amount and gains of the first and second variable gain amplifiers;
• a gain controller to apply the gains associated with the control code to the first and second variable gain amplifiers;
• a detector to detect amplitude and a phase from the combined signal output by the signal combiner;
• a recorder to record, when the gains are applied by the gain controller, a combination of a control code corresponding to said gains and the amplitude and the phase detected by the detector;
• and
• a calibrator to find a phase shift characteristic of the vector summed part from records of the recorder and calibrate the relation between a control code and gains recorded in the table memory by using the phase shift characteristic.

:

• A wireless communication device that mounts a vector sum phase shifter comprising:
• a vector summed part including
• an orthogonal signal generator to generate, from an input signal, a first signal and a second signal which are orthogonal to each other,
• a first variable gain amplifier to amplify the first signal generated by the orthogonal signal generator,
• a second variable gain amplifier to amplify the second signal generated by the orthogonal signal generator, and
• a signal combiner to combine the first signal amplified by the first variable gain amplifier and the second signal amplified by the second variable gain amplifier and output a combined signal of the first signal and the second signal;
• a table memory to store a relation between a control code corresponding to a phase shift amount and gains of the first and second variable gain amplifiers;
• a gain controller to apply the gains associated with the control code to the first and second variable gain amplifiers;
• a detector to detect amplitude and a phase from the combined signal output by the signal combiner;
• a recorder to record, when the gains are applied by the gain controller, a combination of a control code corresponding to said gains and the amplitude and the phase detected by the detector;
• and
• a calibrator to find a phase shift characteristic of the vector summed part from records of the recorder and calibrate the relation between a control code and gains recorded in the table memory by using the phase shift characteristic.