Semiconductor integrated communication circuit and operation method thereof

A method of operating a semiconductor integrated communication circuit to be mounted in a radio communication terminal device, and configured to perform radio frequency communication with a base station in transmit and receive modes, the semiconductor integrated communication

• circuit comprising:
• a low-noise amplifier;
• a receive mixer;
• a receive-voltage-control oscillator;
• a demodulation-signal-processing circuit;
• a modulation-signal-processing circuit;
• a transmit mixer;
• a transmit-voltage-control oscillator;
• and
• a set of a second-order-distortion-characteristic-calibration circuit, a quadrature-receive-signal-calibration circuit, and a test-signal generator, the set allowing the communication circuit to work in a second-order-distortion-characteristic-calibration mode, and a quadrature-receive-signal-calibration mode,
• wherein the low-noise amplifier amplifies an RF receive signal received through an antenna of the radio communication terminal device,
• wherein the receive mixer accepts supply of amplified RF signal from the low-noise amplifier through one input terminal thereof, and supply of an RF receive local signal produced in response to an oscillating output signal of the receive-voltage-control oscillator through the other input terminal,
• wherein the demodulation-signal-processing circuit processes a quadrature-demodulation-receive signal output from an output terminal of the receive mixer thereby to produce a quadrature receive signal,
• wherein, in the receive mode, the receive mixer and demodulation-signal-processing circuit take charge of processing the RF receive signal,
• wherein the modulation-signal-processing circuit handles a quadrature transmit signal,
• wherein the transmit mixer accepts supply of a quadrature transmit output signal from the modulation-signal-processing circuit through one input terminal thereof, and supply of an RF transmit local signal produced in response to an oscillating output signal of the transmit-voltage-control oscillator through the other input terminal,
• wherein, in the transmit mode, the transmit mixer produces and outputs an RF transmit signal in response to an oscillating output signal from the transmit-voltage-control oscillator, and
• wherein the test-signal generator produces a first test signal used in the second-order-distortion-characteristic-calibration mode, and a second test signal used in the quadrature-receive-signal-calibration mode, using an oscillating output signal from the transmit-voltage-control oscillator, and
• wherein the method of operating the semiconductor integrated communication circuit comprises the steps of:
• using the second-order-distortion-characteristic-calibration circuit, in the second-order-distortion-characteristic-calibration mode, to variably change an operation parameter of the receive mixer, thereby to calibrate a second-order distortion characteristic to achieve its best condition while the first test signal from the test-signal generator is supplied to the receive mixer;
• and
• using the quadrature-receive-signal-calibration circuit, in the quadrature-receive-signal-calibration mode, to calibrate phase and amplitude mismatches between in-phase and quadrature-phase components of the quadrature receive signal produced by the demodulation-signal-processing circuit to achieve a best condition of the signal while the second test signal from the test-signal generator is supplied to the receive mixer.