Quadrature Error of Two-Integrator Oscillators

The demand for small-size multi-standard receivers leads to the design of modern receiver architectures with wide tuning range. The performance of these receivers is related to the image rejection ratio, which makes the improvement of the quadrature accuracy mandatory. Hence, minimizing the quadrature error of the receiver's quadrature oscillator is an important goal. In this work, we analyse the sources of quadrature error in the two-integrator oscillator, working in quasi-sinusoidal regime, and propose compensation techniques to minimize the error. Simulation results confirm the amplitude and phase error equations, and show that the quadrature error can be reduced with no impact on the phase noise. We show that the quadrature error increases with the amplitude and circuit component mismatches, and decreases with the amplifier's gains. Based on the theoretical analysis, a novel quadrature error compensation technique to minimize the quadrature error is proposed.