Patent ID: 8331896

Claim:
A method for operating a passive image reject mixer (IRM) comprising: providing a first MOS multiplier with a radio frequency RF+ and RF− input signals; providing said first MOS multiplier with local oscillator LO+ and a LO− input signals; generating an intermediate frequency I IF+ and I IF− output signals responsive of said radio frequency RF+ and RF− input signals, and said local oscillator LO+ and LO− input signals, provided to said first MOS multiplier; generating ninety degree phase shifted LO+ and ninety degree phase shifted LO− output signals from said local oscillator LO+ and LO− input signals, respectively, using a passive phase shifter; providing a second MOS multiplier with said radio frequency RF+ and RF− input signals; providing said first MOS multiplier with said ninety degree phase shifted LO+ and said ninety degree phase shifted LO− output signals; generating IF Q IF+ and Q IF− output signals responsive of said radio frequency RF+ and RF− input signals, and said ninety degree shifted LO+ and LO− output signals, provided to said second MOS multiplier; generating an IF+ output signal responsive to a determination whether the radio frequency is greater or less than a frequency of the local oscillator, and further responsive to said I IF+ output signal and said Q IF+ output signal; and generating an IF− output signal responsive to a determination whether the radio frequency is greater or less than a frequency of the local oscillator, and further responsive to said I IF− output signal and said Q IF− output signal.