Renesas Electronics Corporation

Imec

Sungwoo Cha

Satoshi Tanaka

Taizo Yamawaki

Yukinori Akamine

Koji Maeda

Hiroshi Kamizuma

Kazuaki Hori

Hiroaki Matsui

Satoru Tomisawa

Tetsuya Wakuda

Jonathan Borremans

The present disclosure relates to a method for reducing second order intermodulation distortion in a harmonic rejection mixer arranged for down-converting a radio frequency signal to an in-phase and a quadrature baseband signal. The method includes adjusting an output current of a first mixer, to reduce the second order intermodulation distortion in the quadrature baseband signal to a first value, and adjusting an output current of a second mixer, to reduce the second order intermodulation distortion in the in-phase baseband signal to a second value.

Method for reducing second order distortion in harmonic rejection mixer

There is a need to reduce secondary intermodulation distortion that may occur in a reception circuit of a high-frequency signal processor and a wireless communication system having the same. In test mode, for example, a test signal generating circuit TSGEN generates a test signal RFtst at f_tx&#xb1;0.5 MHz. The test signal RFtst is input to a mixer circuit MIXrx_I (MIXrx_Q). A correction circuit block CALBK detects an IM2 component resulting from the MIXrx_I (MIXrx_Q). The CALBK varies a differential balance for the MIXrx_I (MIXrx_Q) and concurrently monitors a phase for the IM2 component resulting from MIXrx_I (MIXrx_Q). The CALBK searches for the differential balance corresponding to a transition point that allows the phase to transition by approximately 180&#xb0;. The MIXrx_I (MIXrx_Q) operates in normal mode using the differential balance as a search result.

High-frequency signal processor and wireless communication system

There is a need to reduce secondary intermodulation distortion that may occur in a reception circuit of a high-frequency signal processor and a wireless communication system having the same. In test mode, for example, a test signal generating circuit TSGEN generates a test signal RFtst at f_tx &#xb1;0.5 MHz. The test signal RFtst is input to a mixer circuit MIXrx_I (MIXrx_Q). A correction circuit block CALBK detects an IM2 component resulting from the MIXrx_I (MIXrx_Q). The CALBK varies a differential balance for the MIXrx_I (MIXrx_Q) and concurrently monitors a phase for the IM2 component resulting from MIXrx_I (MIXrx_Q). The CALBK searches for the differential balance corresponding to a transition point that allows the phase to transition by approximately 180&#xb0;. The MIXrx_I (MIXrx_Q) operates in normal mode using the differential balance as a search result.

The transmitter of the transceiver includes: a transmitter-side mixers of a transmitter-side modulator; a transmitter-side voltage-controlled oscillator; and a transmitter-side divider. The divider having a dividing factor of a non-integral number is supplied with an oscillating output of the oscillator. A pair of non-quadrature local signals having a phase difference of 90&#xb0; plus a predetermined offset angle is produced by the divider and supplied to the mixers. The transmitter includes a phase-shift unit which converts a pair of quadrature transmit signals having a phase difference of about 90&#xb0; on an analog basis into a pair of non-quadrature shifted transmit signals. Consequently, quadrature modulation is performed by the mixers. Use of a similar configuration enables the reduction in interference of an RF signal with local signals supplied to receiver-side mixers of the receiver.

Transceiver

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Takasaki, Japan

Sungwoo Cha