New first- and second-order very low sensitivity bandpass/bandstop complex digital filter sections

Very low magnitude sensitivity first- and second-order bandpass and bandstop complex coefficient orthogonal digital filter structures are derived by developing appropriate prototype sections and applying on them a circuit transformation. The bandstop and the multioutput universal orthogonal sections are proposed for first time. Then, a comparative study together with other known structures is conducted and it is shown that while having a canonic (minimum) number of multipliers and delay elements (many times less than those of the other known structures), the new structures have tens or hundreds of times lower sensitivity for narrow-band realizations. A method of approximation and design of higher orthogonal filters employing the new sections also is proposed. The lower sensitivity of the new structures is demonstrated experimentally.