Abstract: An imbalance compensation system includes a receiver, a first path and a second path electrically coupled to the receiver, and a 90 degree hybrid coupler electrically connected to the second path, wherein the first path is configured to convey an in-phase (I) signal and the second path is configured to convey a quadrature phase (Q) signal. A processor is configured to perform Finite Impulse Response (FIR) filtering upon the I signal and the Q signal, wherein the processor is configured with an inverse matrix of coefficients corresponding to a frequency-dependent phase imbalance and a frequency-dependent amplitude imbalance between the I signal and the Q signal. The processor is configured to perform FIR filtering to attenuate an image signal down to a system noise floor when the processor simultaneously receives signals in a primary Nyquist region and a conjugate Nyquist region.

Abstract: A new approach for applying the multiple signal classification (MUSIC) method for high spectral resolution signal detection is described. The new approach uses a lower order covariance matrix, or, alternately, an autocorrelation matrix, to calculate only the number of eigenvalues and associated eigenvectors actually needed to solve for the number of signals sought.