Abstract: A harmonic-rejection modulation device is provided, which includes a phase splitter, a low pass filter, and a modulator. Based on a square wave, the phase splitter generates a plurality of unfiltered local oscillating signals having phase angles of 0°, 30°, 90°, 120°, 180°, 210°, 270° and 300°, respectively. The low pass filter filters the high frequency components of the unfiltered local oscillating signals to generate a plurality of local oscillating signals having phase angles of 0°, 30°, 90°, 120°, 180°, 210°, 270° and 300°, respectively. The modulator modulates a baseband signal with the local oscillating signals, wherein the third harmonics of the local oscillating signals are eliminated by the modulation process of the modulator. The invention also provides a method of modulating a baseband signal.

Abstract: A mixer of a homodyne RF receiver made from a CMOS process is provided. The mixer comprises a gain stage, a switch stage and a load stage. The gain stage receives a differential-typed RF signal and generating a first gained signal. The switch stage mixes the first gained signal and a LO signal to direct down-convert into a modulated signal. The load stage comprises a first transistor, an impedance element and a second transistor. The first transistor provides a low impedance to permit the modulated signal entering the load stage. The second transistor provides a high impedance to resist signals. The load stage converts the modulated signal to a second gained signal according to a first gain coefficient of the impedance element. The first transistor is a parallel pnp BJT, and the second transistor is a vertical npn bipolar BJT.

Abstract: A harmonic-rejection modulation device is provided, which includes a phase splitter, a low pass filter, and a modulator. Based on a square wave, the phase splitter generates a plurality of unfiltered local oscillating signals having phase angles of 0°, 30°, 90°, 120°, 180°, 210°, 270° and 300°, respectively. The low pass filter filters the high frequency components of the unfiltered local oscillating signals to generate a plurality of local oscillating signals having phase angles of 0°, 30°, 90°, 120°, 180°, 210°, 270° and 300°, respectively. The modulator modulates a baseband signal with the local oscillating signals, wherein the third harmonics of the local oscillating signals are eliminated by the modulation process of the modulator. The invention also provides a method of modulating a baseband signal.

Abstract: A mixer of a homodyne RF receiver made from a CMOS process is provided. The mixer comprises a gain stage, a switch stage and a load stage. The gain stage receives a differential-typed RF signal and generating a first gained signal. The switch stage mixes the first gained signal and a LO signal to direct down-convert into a modulated signal. The load stage comprises a first transistor, an impedance element and a second transistor. The first transistor provides a low impedance to permit the modulated signal entering the load stage. The second transistor provides a high impedance to resist signals. The load stage converts the modulated signal to a second gained signal according to a first gain coefficient of the impedance element. The first transistor is a parallel pnp BJT, and the second transistor is a vertical npn bipolar BJT.

Abstract: A VCO system embodying the features of the present invention includes a frequency tuning circuit, a modulation circuit coupled in a parallel fashion with the frequency tuning circuit, a band tuning circuit coupled with the frequency tuning circuit in a parallel fashion having at least one switching circuit, a core circuit coupled with the frequency tuning circuit, the modulation circuit, and the band tuning circuit, wherein upon asserting a switching signal and upon adjusting a frequency turning signal, a frequency tuning bias signal, and a band tuning signal, the switching circuit is enabled for configuring the band tuning circuit to join the frequency tuning circuit for adjusting a predetermined output frequency based on a total inductance and a total capacitance provided by the core circuit, the frequency tuning circuit, the modulation circuit and the band tuning circuit.

Abstract: A VCO system embodying the features of the present invention includes a frequency tuning circuit, a modulation circuit coupled in a parallel fashion with the frequency tuning circuit, a band tuning circuit coupled with the frequency tuning circuit in a parallel fashion having at least one switching circuit, a core circuit coupled with the frequency tuning circuit, the modulation circuit, and the band tuning circuit, wherein upon asserting a switching signal and upon adjusting a frequency turning signal, a frequency tuning bias signal, and a band tuning signal, the switching circuit is enabled for configuring the band tuning circuit to join the frequency tuning circuit for adjusting a predetermined output frequency based on a total inductance and a total capacitance provided by the core circuit, the frequency tuning circuit, the modulation circuit and the band tuning circuit.