Gain-phase mismatch correction technique for I/Q channel receiver

Every communication receiver that uses in-phase and quadrature channel signal processing technique encounters problems related to matching of gain and phase in both the channels. The gain and phase imbalances occur between Low Pass Filter and Local Oscillator used in both the channels and as a result the performance of the receivers and the quality of the received signals are degraded. The imbalances produced may cause insufficient attenuation in image frequency band leading to interference. The problem needs to be compensated. This paper represents novel architecture design and implementation of COordinate Rotation DIgital Computer (CORDIC) algorithm based Adaptive FIR filter using Trigonometric Least Mean Square (TLMS) algorithm to give a solution for correcting I/Q imbalances. The design of CORDIC in the vector rotation mode results in high system throughput due to its pipelined architecture where latency is reduced in each of the pipelined stage and finds its appropriate application in real time signal processing. The good convergence of CORDIC in the given LMS algorithm based adaptive filter facilitates in easy calculation of new filter weights.

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