Via Technologies, Inc.

Intel Corporation

Sen-You Liu

Shih-An Yu

Did-Min Shih

Fang-Ren Liao

Pi-An Wu

Ying-Che Tseng

Nean-Chu Cheng

Che-Hung Liao

Yu-Hong Lin

Jung-Chang Liu

Yi-Pei Su

A voltage-controlled oscillator gain measurement system includes a voltage-controlled oscillator, a voltage detector, and a processor. The voltage-controlled oscillator, which is configured in a phase-locked loop circuit, generates an output signal with an output frequency according to a control signal. The control signal is generated according to the output signal divided by a scaling number. The voltage detector is configured to measure a voltage difference of the control signal. The processor adjusts the scaling number to generate an output frequency difference of the output signal, and obtains a reciprocal gain of the voltage-controlled oscillator by dividing the voltage difference by the output frequency difference.

Devices and methods of measuring gain of a voltage-controlled oscillator

A phase-locked loop circuit includes a phase detector, a charge pump, a capacitor, and a capacitor multiplier. The phase detector receives a reference frequency and a feedback frequency to generate a up/down signal. The charge pump, which includes a positive node and a negative node, receives the up/down signal to generate a first current. The capacitor is coupled to the negative node. The capacitor multiplier, coupled to the negative node, generates a second current which is the first current divided by a first scaling number.

Phase-locked loop circuit with improved performance

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&#xb0;, 30&#xb0;, 90&#xb0;, 120&#xb0;, 180&#xb0;, 210&#xb0;, 270&#xb0; and 300&#xb0;, 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&#xb0;, 30&#xb0;, 90&#xb0;, 120&#xb0;, 180&#xb0;, 210&#xb0;, 270&#xb0; and 300&#xb0;, 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.

Harmonic-rejection modulation device

A divide-by-N/(N+0.5) frequency divider is disclosed. Two pairs of flip-flops are respectively triggered by an input clock and an inverted input clock, and a frequency-dividing selector is used to select one output of the two pairs of flip-flops as frequency-divided output signal. Two latches are respectively triggered by the input clock and the inverted input clock, and a modulus selector is used to select one output of the two latches. A modulus logic circuit determines being in either N frequency-dividing mode or (N+0.5) frequency-dividing mode based on a modulus control signal. A frequency-dividing logic circuit receives output of the modulus logic circuit and an inverted frequency-divided output signal to swallow half the input clock per output cycle in the (N+0.5) frequency-dividing mode, therefore obtaining division resolution of half the input clock.

Fractional frequency divider

A mobile system has a frequency synthesizer and an amplifier module coupled to the frequency synthesizer. The frequency synthesizer is controlled by frequency division data to generate a tuning signal with a frequency corresponding to a reference signal and the frequency division data. The mobile system provides an input signal based on the frequency of the tuning signal having a frequency spectrum corresponding to the frequency of the tuning signal. The amplifier module has a variable load circuit for providing an equivalent impedance, an amplifier circuit coupled to the variable load circuit for establishing an output signal corresponding to the input signal and the equivalent impedance of the variable load circuit, and a mapping circuit for modifying the equivalent impedance of the variable load circuit based on the frequency division data.

Communications system with variable load and related method

A phase-frequency detector generates output signals at a first and a second output end based on input signals received at a first and a second input end. The phase-frequency detector includes two latch circuits, two pulse generators, two inverting circuits, two sensing devices, and a reset control circuit. The sensing devices control the pulse generators based on signals received at corresponding first ends of the sensing devices. The inverting circuits generate signals to the first and second output ends of the phase-frequency detector based on signals received at corresponding first ends of the inverting circuits. The reset control circuit generates reset signals based on signals received at the first and second output ends of the phase-frequency detector.

Phase-frequency detector capable of reducing dead zone

A power amplifier circuit amplifying an input signal to an output signal and a method thereof. The power amplifier circuit comprises a ramp controller, a current source, and a first amplification stage. The ramp controller receives an enable signal to generate a ramp signal. The current source is coupled to the ramp controller, produces a ramp current by the ramp signal. The first amplification stage is coupled to the current source, comprises a first supply voltage input coupled to a fixed supply voltage, and is biased by the ramp current to amplify the input signal such that an envelope of the output signal is a ramp.

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Taipei, Taiwan

Sen-You Liu