Down/up-conversion mixer for direct conversion radios

A radio frequency (RF) receiver comprising:

• a receiver front-end circuit capable of receiving an incoming RF signal from an antenna and filtering and amplifying said incoming RF signal;
• and
• a radio frequency (RF) down/up-conversion circuit coupled to said receiver front-end circuit comprising:
• a local oscillator chopping circuit comprising:
• a frequency divider circuit capable of receiving a first local oscillator (LO) signal having a frequency of LO and generating therefrom a frequency-divided second local oscillator (LO) signal having a frequency of LO/N and synchronized with said first LO signal;
• and
• a multiplier capable of receiving said first and second LO signals and generating a signal that during selected periods of time has a signal polarity that is reversed relative to a signal polarity of said first LO signal;
• and
• a differential radio frequency (RF) mixer having a first differential input port capable of receiving said signal from said multiplier and a second differential input port capable of receiving a first differential modulated radio frequency (RF) signal and a second differential modulated radio frequency (RF) signal, wherein said differential RF mixer generates a differential output signal.

A method of demodulating an incoming differential radio frequency (RF) signal having a frequency of RF comprising the steps of:

• receiving a first local oscillator (LO) signal having a frequency of LO;
• generating therefrom a frequency-divided second local oscillator (LO) signal having a frequency of LO/N and synchronized with the first LO signal;
• multiplying the first and second LO signals and generating a product signal of the first and second LO signals that during selected periods of time has a signal polarity that is reversed relative to a signal polarity of said first LO signal;
• and
• mixing the product signal from the multiplier and the differential radio frequency signal and generating a differential output signal.