Future Wei Technologies, Inc.

Seong-Mo Yim

Feng Wang

Robert Irvine

Yusong Chi

Ping Yin

Chengfang Liao

Eric Sung

A noise cancellation system comprises a first noise cancellation apparatus configured to process an I-channel signal, wherein an I-channel differential mode second-order intermodulation component and an I-channel common mode second-order intermodulation component cancel each other in the first noise cancellation apparatus and a second noise cancellation apparatus configured to process a Q-channel signal, wherein a Q-channel differential mode second-order intermodulation component and a Q-channel common mode second-order intermodulation component cancel each other in the second noise cancellation apparatus.

Noise cancellation system

A noise cancellation system comprises an I-channel mixer configured to receive a radio frequency signal from an antenna and an intermediate frequency signal from a local oscillator, a Q-channel mixer configured to receive the radio frequency signal from the antenna and a phase-shifted intermediate frequency signal from the local oscillator, a first noise cancellation apparatus connected with the I-channel mixer, wherein an I-channel differential mode second-order intermodulation component and an I-channel common mode second-order intermodulation component cancel each other in the first noise cancellation apparatus and a second noise cancellation apparatus connected with the Q-channel mixer, wherein a Q-channel differential mode second-order intermodulation component and a Q-channel common mode second-order intermodulation component cancel each other in the second noise cancellation apparatus.

A noise cancellation structure comprises a trans-impedance stage couple to an output of a mixer of a receiver and a noise cancellation stage connected in parallel with the trans-impedance stage, wherein the noise cancellation stage comprises a first adjustable resistor and a second adjustable resistor connected in series with the first adjustable resistor, wherein the first adjustable resistor and the second adjustable resistor are configured such that the first adjustable resistor has a first resistance variation portion and the second adjustable resistor has a second resistance variation portion equal to the first resistance variation in an opposite direction and a magnitude of the first resistance variation is so selected that differential mode second-order noise and common mode second-order noise cancel each other.

Noise cancellation apparatus and method

A receiver compensation method comprising receiving a radio frequency signal, amplifying the radio frequency signal, thereby producing an amplified signal, compensating the amplified signal, thereby producing a compensated signal, and mixing the compensated signal, thereby producing a mixed compensated signal, wherein the mixed compensated signal has a first gain difference between a positive differential from a center frequency and a negative differential from the center frequency and wherein the first gain differential is smaller than a second gain differential that would be obtained by mixing the amplified signal without compensating the amplified signal.

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Oak Ridge, NC, United States of America

Seong-Mo Yim