Very Low Sensitivity Complex Coefficients Band-Pass Filter Sections

Abstract After development and proper selection and investigation of different prototype low-pass sections, very low magnitude sensitivity first- and second-order complex coefficient orthogonal digital filter structures are derived. Then, a comparative study together with other known structures is conducted and it is shown that, by having canonic (minimum) number of multipliers and delay elements, the new structures employ more than two times (for first-order) and more than three times (for second-order) less elements, ensuring in the same time tens or hundreds of times lower sensitivity for narrow-band realizations. It is demonstrated experimentally that the new structures are preserving their magnitude responses even when the coefficient word-length is reduced to 2 bits of canonic SD-code, while the response of the other known structures are totally destroyed even with 3 bits word-length. The new structures are suitable for realization of high quality narrow-band orthogonal filters of higher order. Key words Digital IIR filters, complex coefficients filters, orthogonal filters, low sensitivity I