Ali Corporation

Hou-Kuan Sung

Kuo-Kai Lin

Yue-Yong Chen

Chih-Yu Chuang

A digital video broadcast receiver including a frequency synthesizer, a plurality of frequency dividing-phase shifting circuits, an antenna and a plurality of signal processing modules is provided. The frequency synthesizer synthesizes a first frequency signal. The frequency dividing-phase shifting circuits individually perform a frequency dividing-phase shifting operation on the first frequency signal to generate a plurality of first signals having different frequencies and a plurality of second signals corresponding to the first signals, where each of the first signals is orthogonal to the corresponding second signal. The antenna receives a radio frequency signal. The signal processing modules respectively obtain a plurality of signal components belonging to different sub-bands from the radio frequency signal according to the first signals and the second signals.

Digital video broadcast receiver

A signal generating circuit includes a detecting circuit, a charge pump, a first level shifter, a filtering circuit, a second level shifter and a controllable oscillator. The detecting circuit outputs a detecting signal according to a reference signal and an oscillating signal. The charge pump outputs a first output signal by performing a charging or discharging operation according to the detecting signal. The first level shifter adjusts a voltage level of the first output signal to thereby output a second output signal. The filtering circuit generates a first filtered control signal according to the second output signal. The second level shifter adjusts a voltage level of the first filtered controlling signal to output a second filtered control signal. The controllable oscillator outputs the oscillating signal according to the second filtered control signal.

Signal generating circuit having filtering circuit coupled between level shifters

A phase locked loop device is provided. The phase locked loop device includes a phase/frequency detector, a charge pump, a low pass filter, a voltage-controlled oscillator, and a control unit. The phase/frequency detector generates a compared signal corresponding to a phase difference between a reference clock signal and a feedback clock signal. The charge pump coupled to the phase/frequency detector generates a pump current according to the compared signal. The low pass filter coupled to the charge pump generates an operating voltage corresponding to the pump current. The voltage-controlled oscillator coupled to the low pass filter generates an output clock signal in response to the operating voltage. The control unit coupled to the low pass filter and the voltage-controlled oscillator constrains the operating voltage to a predetermined voltage level when the frequency of the output clock signal is out of a predetermined frequency range.

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Taipei, Taiwan

Hou-Kuan Sung