Patent ID: 6734820
Filing Date: 2004-05-11
Classification: G01S

Abstract:
An in-phase/quadrature component (IQ) mixer, said mixer configured to reject returns from a negative doppler shift swath in order to mitigate corruption of a positive doppler shift swath, said mixer comprising:a sample delay element configured to produce a quadrature component of the returned swaths; a plurality of mixer elements, at least one said mixer element configured to sample an in-phase component of the returned swaths at a pulse repetition interval, at least one said mixer element configured to sample the quadrature component at a pulse repetition interval; a plurality of low pass filters electrically connected to outputs of said mixer elements, at least one said low pass filter configured to filter the in-phase component, at least one said low pass filter configured to filter the quadrature component; a plurality of decimators electrically connected to outputs of said low pass filters, at least one said decimator configured to down sample the in-phase component to a doppler frequency, at least one said decimator configured to down sample the quadrature component to the doppler frequency; a plurality of all pass filters electrically connected to outputs of said decimators, at least one said all pass filter configured to filter the down sampled in-phase component, at least one said all pass filter configured to filter the down sampled quadrature component; and a subtraction element electrically connected to outputs of said all pass filters, said subtraction element configured to subtract the filtered and down sampled quadrature component from the filtered and down sampled in-phase component.