Reciprocal mixing noise cancellation in the presence of a modulated blocker

A system for reciprocal mixing noise cancellation, the system comprising:

• a first mixer configured to generate a first signal comprising a wanted signal at a first frequency and a modulated signal at a second frequency, the modulated signal resulting from a reciprocal-mixing of an unwanted signal with a phase noise, wherein the second frequency is greater than the first frequency, and at least a portion of the modulated signal overlaps the wanted signal, adding a reciprocal-mixing noise to the wanted signal;
• a second mixer configured to generate a second signal by mixing the first signal with a third signal, the third signal being a narrow signal at a third frequency, wherein the third frequency is related to a blocker offset frequency;
• a gain stage configured to amplify the second signal and to generate an amplified second signal;
• a subtraction module configured to subtract the amplified second signal from the first signal to generate a fourth signal;
• and
• a filter configured to filter the fourth signal to remove a reciprocal-mixing noise and generate the wanted signal at the first frequency without the reciprocal-mixing noise.

A communication device comprising:

• memory to store one or more program modules;
• and
• one or more processors couple to the memory and configured to execute the one or more program modules to:
• receive a first signal from a first mixer, the first signal comprising a wanted signal at a first frequency and a modulated signal at a second frequency, the modulated signal resulting from a reciprocal-mixing of an unwanted signal with a phase noise, wherein the second frequency is greater than the first frequency, and at least a portion of the modulated signal overlaps the wanted signal, adding a reciprocal-mixing noise to the wanted signal;
• generate a second signal by mixing at a second mixer the first signal with a third signal, the third signal being a narrow signal at a third frequency, wherein the third frequency is related to a blocker offset frequency;
• apply a gain to the second signal and generate an amplified second signal;
• subtract the amplified second signal from the first signal and generate a fourth signal;
• and
• filter the fourth signal and remove a reciprocal-mixing noise and generate the wanted signal at the first frequency without the reciprocal-mixing noise.