Frequency synthesizer circuit
AssigneeFujitsu Limited
InventorsToshiro Motoyoshi, Kimihiko Nagata
Life of this patent
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Abstract
The frequency synthesizer circuit includes a phase-locked loop (PLL) circuit, a voltage controlled oscillator (VCO), a low pass filter (LPF), an input terminal for providing serial data provided from the exterior to the PLL circuit, an output terminal for providing an oscillation signal provided the VCO, and a testing unit providing a testing voltage with a binary value to the VCO, wherein, the PLL circuit, the VCO, the LPF, and the testing unit are mounted on a single chip, and usability of the frequency synthesizer circuit is determined based on the oscillation signal provided from the VCO via said output terminal according to the testing voltage with a binary value provided from said testing unit.
Claims8
A frequency synthesizer circuit comprising:
- a phase-locked loop circuit;
- a voltage controlled oscillator;
- a low pass filter;
- an input terminal for providing serial data provided from the exterior to said phase-locked loop circuit;
- an output terminal for providing an oscillation signal provided from said voltage controlled oscillator;
- and
- a testing unit providing a testing voltage with a binary value to said voltage controlled oscillator, wherein,
- said phase-locked loop circuit, said voltage controlled oscillator, said low pass filter, and said testing unit are mounted on a single chip;
- and
- usability of said frequency synthesizer circuit is determined based on the oscillation signal provided from said voltage controlled oscillator via said output terminal according to the testing voltage with a binary value provided from said testing unit.
A frequency synthesizer circuit comprising:
- a voltage controlled oscillator;
- a phase-locked loop circuit receiving an oscillation signal provided from said voltage controlled oscillator and a given signal in order to generate a phase difference signal by detecting a phase difference between the oscillation signal and the given signal;
- a testing unit providing a predetermined testing voltage to said voltage controlled oscillator, wherein
- said phase-locked loop circuit further receives serial data provided from the exterior in order to provide a control signal to said testing unit;
- said testing unit provides the predetermined testing voltage according to the control signal provided from said phase-locked loop circuit;
- and
- said voltage controlled oscillator provides the oscillation signal based on the phase difference signal provided from the phase-locked loop circuit in a normal operation mode and provides the oscillation signal based on the predetermined testing voltage provided from said testing unit in a testing operation mode.
Dependencies are inferred from the claim text.