In a radio receiver, the antenna consists of a linear array of three uniformly spaced isotropic sensors, separated by the distance d = λ/2, where λ is the wavelength of the carrier frequency f0, i.e., λ = c/f0 and is the velocity of light. The useful signal is arriving from the incidence angle θ = π/6 with respect to the array. The base-band signal received by the center element in the array, after frequency shift and sampling, is expressed by
Give the relationship between the coefficients α and ß necessary to cancel a jammer arriving from incidence angle 0 (orthogonal to the array). Compute the coefficients that maximize the output signal-tonoise ratio.