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US 7,003,270 B2Granted
Electronic apparatus having radio transmitter
AssigneeFujitsu Limited
InventorsNobuhide Maruo, Makoto Saotome, Makoto Kotani
Life of this patent
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Abstract
An electronic apparatus comprising a radio transmitter is disclosed. In a computer system (1) having a radio transmission circuit (3) of a phase modulation type supplied with power from a power supply (4) of a switching type, the switching frequency of the power supply (4) is determined based on the comparison frequency for the sampling operation of a PLL circuit (10) of the radio transmitter, thereby removing the power noises generated from the switching regulator of the radio transmitter of a phase modulation type.
Claims2
An electronic communication apparatus, comprising:
- a phase modulation radio transmitter, comprising:
- a phase lock loop (PLL) circuit having an oscillation circuit and a phase detection circuit receiving a first input signal from the oscillation circuit and a second input signal from the output of the PLL circuit, the second input signal having a comparison frequency;
- a modulation circuit receiving the signal output from the PLL circuit;
- and
- a switchable power supply supplying power to the PLL circuit, the switchable power supply having a switching frequency which is equal to the comparison frequency of the second input signal.
2 more elements
Dependencies are inferred from the claim text.