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US 2010/0073095 A1Published application
Frequency Synthesizer and Radio Transmitting Apparatus
AssigneePanasonic Corporation
InventorShunsuke Hirano
Life of this patent
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Abstract
A frequency synthesizer (100) can selectively set an output band of VCO, and consumes less power. The frequency synthesizer (100) has a frequency converting circuit (110) that has a mixer (111) and a frequency divider (112) connected with each other in parallel. The frequency synthesizer (100) uses the frequency divider (112) upon frequency band selection in VCO (101) and uses the mixer (111) upon transmission.
Claims6
A frequency synthesizer comprising:
- a voltage control oscillator that covers a plurality of selectable oscillation frequency bands and that oscillates a signal of a frequency matching a voltage applied to a control voltage terminal;
- a frequency converting circuit that comprises a mixer and a frequency divider connected with each other in parallel and that down-converts a frequency of an output signal of the voltage control oscillator using selectively one of the mixer and the frequency divider;
- a comparator that compares a signal outputted from the frequency converting circuit, with a reference signal, and outputs a comparison result signal;
- and
- a loop filter that smoothes the comparison result signal and outputs the smoothed signal to the control voltage terminal of the voltage control oscillator.
2 more elements
Dependencies are inferred from the claim text.