Patent ID: 7295824
Filing Date: 2007-11-13
Classification: H03L

Abstract:
1. A WLAN (Wireless Local Area Network) communication device comprising a WLAN frequency synthesizer arranged to generate a synthesizer signal suitable for modulating a transmission signal and/or demodulating a reception signal, wherein the WLAN frequency synthesizer comprises: a reference oscillator arranged to generate a first reference clock signal; a fractional-N PLL (Phase-Locked Loop) unit arranged to receive a second reference clock signal and to convert the second reference clock signal into the synthesizer signal; and a frequency multiplier arranged to receive the first reference clock signal and to convert the first reference clock signal into the second reference clock signal to be forwarded to said fractional-N PLL unit by multiplying the frequency of the first reference clock signal by a multiplication factor; wherein the fractional-N PLL unit comprises a VCO (Voltage Controlled Oscillator) oscillator arranged to output the synthesizer signal and a loop filter arranged to generate a control voltage for controlling the operation of the VCO oscillator; and wherein the loop filter is further arranged to operate at a loop filter bandwidth narrower than or equal to one percent of the frequency of the second reference clock signal and broader than one percent of the frequency of the first reference clock signal.