Realtek Semiconductor Inc.

Chia-jun Chang

Kuan-Yu Shih

Yang Chang

Yi-Ching Wu

Ka-Un Chan

A frequency mixing circuit includes: a first transistor and a second transistor. The first transistor has a control terminal, a first terminal and a second terminal. The control terminal of the first transistor is configured to receive an oscillation signal, the first terminal of the first transistor is configured to output a mixed signal, and the second terminal of the first transistor is configured to receive a source signal. The second transistor has a control terminal, a first terminal and a second terminal. The control terminal of the second transistor is coupled to the second terminal of the first transistor, the first terminal of the second transistor is coupled to the first terminal of the first transistor, and the second terminal of the second transistor is coupled to the control terminal of the first transistor.

Frequency mixing circuit with multi-transistor architecture

A resistive attenuator and a method for improving linearity of the resistive attenuator are provided. The resistive attenuator includes a first transistor, an attenuation circuit and a compensation circuit, wherein both the first transistor and the attenuation circuit are coupled between an input terminal and an output terminal of the resistive attenuator, and the compensation circuit is coupled to the first transistor. The first transistor is configured to provide a first signal path between the input terminal and the output terminal. The attenuation circuit is configured to provide a second signal path between the input terminal and the output terminal, wherein signal attenuation of the second signal path is greater than signal attenuation of the first signal path. The compensation circuit is configured to compensate nonlinear distortion caused by the first transistor.

Resistive attenuator and method for improving linearity of resistive attenuator

The present invention discloses a variable gain amplifier circuit having linearity compensation mechanism is provided. A lower amplification transistor of a lower branch of an amplification circuit is controlled by an AC input signal. Upper amplification transistors of an upper branch generate an AC output signal at an amplification output terminal. An amplification control circuit controls the turn-on and turn-off of the upper amplification transistor according to an amplification control voltage. An inductor is electrically coupled between a power supply terminal and the amplification output terminal. In a gain adjustment circuit, each of adjustment control circuits controls the turn-on and turn-off of each of adjustment transistors according to a adjustment control voltage. A first voltage adjustment circuit adjusts an impedance of each of the adjustment transistors to further adjust an AC cross voltage relation between the lower amplification transistor and the upper amplification transistors.

Variable gain amplifier circuit and method having linearity compensation mechanism

A wireless transceiver having an in-phase quadrature-phase (IQ) calibration function includes a transmitter, a receiver, a signal generator, and a switch circuit. The switch circuit includes a first and a second switch circuits. The first switch circuit is turned on in a receiver-end calibration process, and outputs a predetermined signal from the signal generator to the transmitter. The second switch circuit is turned on in the receiver calibration process and outputs a derivative signal of the predetermined signal from the transmitter to the receiver to let the receiver performs a receiver-end IQ calibration accordingly. The first switch circuit is turned off and the second switch circuit is turned on in a transmitter-end calibration process; the second switch circuit outputs a radio-frequency signal from the transmitter to the receiver to let the receiver generates a calibration reference accordingly; and the transmitter performs a transmitter-end IQ calibration according to the calibration reference.

Wireless transceiver having in-phase quadrature-phase calibration function

An amplifier device includes a regulator circuit, a first voltage converting circuit, a first control circuit, and an amplifier circuit. The regulator circuit is configured to output a first driving voltage. The first voltage converting circuit is coupled to the regulator circuit, and is configured to output one of the first driving voltage and at least one first voltages related to the first driving voltage, as a first operating voltage. The first control circuit is coupled to the first voltage converting circuit through a first node, and is configured to receive the first operating voltage and generate a first operating signal according to the first operating voltage and a first control signal. The amplifier circuit is coupled to the first control circuit and the regulator circuit, and is configured to receive the first driving voltage, and is controlled by the first operating signal to generate an output voltage.

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HSINCHU, Taiwan

Chia-jun Chang