Abstract: A circuit for reducing counter-intermodulation in a modulated signal caused by an oscillator frequency and harmonics of a baseband signal is disclosed. The circuit comprises a first and a second baseband section arranged for generating a first and a second version of a baseband signal, the second version being phase shifted with respect to the first version. The circuit further comprises three signal paths comprising mixers for multiplication of the first and second version of the baseband signal with a local oscillator signal, so that three upconverted signals with rotated phase with respect to each other are obtained, and arranged for applying a scaling with a scaling factor corresponding to the rotated phases. The circuit further comprises a combination unit arranged for combining the three upconverted signals.

Abstract: Thermally stabilized resonant electro-optic modulator (1), wherein the temperature control unit (8) is provided for separately determining the first and the second intensities measured by the light sensor (6) at the first voltages and the second voltages respectively in function of time.

Abstract: Thermally stabilised resonant electro-optic modulator (1), wherein the temperature control unit (8) is provided for separately determining the first and the second intensities measured by the light sensor (6) at the first voltages and the second voltages respectively in function of time.

Abstract: A circuit for reducing counter-intermodulation in a modulated signal caused by an oscillator frequency and harmonics of a baseband signal is disclosed. The circuit comprises a first and a second baseband section arranged for generating a first and a second version of a baseband signal, the second version being phase shifted with respect to the first version. The circuit further comprises three signal paths comprising mixers for multiplication of the first and second version of the baseband signal with a local oscillator signal, so that three upconverted signals with rotated phase with respect to each other are obtained, and arranged for applying a scaling with a scaling factor corresponding to the rotated phases. The circuit further comprises a combination unit arranged for combining the three upconverted signals.

Abstract: A voltage controlled oscillator with automatic center frequency calibration. The frequency range of the oscillator is increased by switchable capacitor circuits which add or remove extra capacitors in parallel with the variable capacitor of the resonant circuit. Different voltage versus frequency characteristics are obtained. The switchable capacitor circuits are controlled by a detection circuit that sends a reset pulse to a feedback circuit of the VCO when a control voltage from the feedback circuit reaches predetermined low or high voltage limits of the characteristics. Upon reception of the reset pulse, the feedback circuit changes the control voltage from the reached limit into an intermediate voltage between the low and high voltage limits. The control voltage is reset in the middle of a voltage versus frequency characteristic onto which the output frequency is also centered. The VCO includes a selection circuit adapted to immediately change the value of the control voltage.

Abstract: A voltage controlled oscillator with automatic center frequency calibration. The frequency range (FOUT) of the oscillator is increased because of the presence of switchable capacitor circuits (SW1, XC1; SW2, XC2) which add or remove extra capacitors (XC1; XC2) in parallel with the variable capacitor (CV) of the resonant circuit (CV, L). Different voltage versus frequency characteristics (CHL, CHM, CHH) are so obtained. The control of the switchable capacitor circuits is performed by a detection circuit (DET). The detection circuit is further adapted to send a reset pulse (RES) to a feedback circuit (FB) of the VCO when a control voltage (VCTRL), provided by the feedback circuit, reaches predetermined low (VTL) or high (VTH) voltage limits of the characteristics. Upon reception of the reset pulse, the feedback circuit changes the control voltage from the reached limit into an intermediate voltage (VTM) in the middle of the range between the low and the high voltage limits.