US Patent 7890078 Dual band WLAN communication frequency synthesizer technique

A dual band WLAN (Wireless Local Area Network) communications technique is provided where a frequency synthesizer unit generates an LO (Local Oscillator) signal at a frequency between both frequency bands and two downconversion units and/or two upconversion units are provided. One of the units performs conversion between the LO signal and an IF (Intermediate Frequency) signal while the other conversion takes place between the IF signal and a zero-IF or low-IF signal. Signal processing is performed on the zero-IF or low-IF signal.