Mediatek Corporation

Tai Yuan Yu

Ling-Wei Ke

Hsin-Hung Chen

Ping-Ying Wang

Bing-Yu Hsieh

Tser-Yu Lin

A phase locked loop (PLL) with a loop bandwidth calibration circuit is provided. The mixed-mode PLL comprises an analog phase correction path, a digital frequency correction path, a calibration current source, and a loop bandwidth calibration circuit. The analog phase correction path comprises a linear phase correction unit (LPCU). The digital frequency correction path comprises a digital integral path circuit. The calibration current source is coupled to the LPCU. The loop bandwidth calibration circuit is coupled to a frequency divider and coupled between the input and output of the PLL. The loop bandwidth calibration circuit operates after the calibration current source injects a calibration current into the LPCU.

PLL with loop bandwidth calibration circuit

A phase locked loop frequency synthesizer including a phase locked loop, a frequency regenerator and a modulation processor, resistant to distortion induced by the frequency regenerator and conforming to transmission specifications. The phase locked loop comprises a detector generating a phase detection signal based on phase difference between a reference signal and a feedback signal, a loop filter, a voltage control oscillator generating a first output modulation signal and a frequency dividing unit varying a division factor based on a processed input modulation signal and dividing the frequency of the first output modulation signal by a division factor to generate the feedback signal. The frequency regenerator generates a second output modulation signal with a frequency range not overlapping an output frequency range of the voltage control oscillator. The modulation processor generates the processed input modulation signal to adjust the division factor of the frequency dividing unit and compensating for distortion induced by the frequency regenerator.

Phase locked loop frequency synthesizer and method for modulating the same

A dynamic carrying method to prevent saturation of a sigma-delta modulator of a phase locked loop frequency synthesizer. The phase locked loop frequency synthesizer using the dynamic carrying method comprises a forward portion receiving a reference frequency signal and a first frequency signal to generate an output carrier signal; a multi-modulus divider dividing the output carrier signal frequency to generate the first frequency signal; a dynamic carrying device receiving and separating transmitting data into a carrying part and a residue part when the transmitting data amplitude exceeds a threshold; a sigma-delta modulator receiving the residue part to generate a first modulus control signal; an auxiliary modulator receiving the carrying part to generate a second modulus control signal; and a first adder receiving the first modulus control signal, the second modulus control signal, and a third modulus control signal and outputting a modulus modulation signal to modulate the multi-modulus divider.

Growing community of inventors

Taoyuan Hsien, Taiwan

Tai Yuan Yu