In this paper, the sensitivity analysis of the elliptic filters realized by using biquadratic structures was carried out. The influence

of spread the structure parameter values on the shape of the frequency characteristic of the filter transmittance modulus was analyzed. The analysis was limited to the case of even order low-pass filter. Defining the proper class of the sensitivity coefficients, the changes influence of individual structure parameters on the deviation of basic parameter values of the characteristic was considered. The considerations were illustrated by the numerical example.

The influence of bandwidth of OPA on frequency characteristics was investigated in this paper. The analysis of frequency properties was carried out for two exemplary structures. For operational amplifier it was assumed a typical frequency macromodel with 1-pole characteristic. Deformation of the frequency characteristic and the structure bandwidth in dependence on amplifiers bandwidth were analyzed. It was proved that shape of the characteristic to some degree depends on some elements values. The procedure was proposed for optimal choice of the values of (RC) elements, that ensures the characteristic is most approached to ideal one. Optimal values of these (RC) elements ensure that the characteristic of structures do not have any distortion in all frequencies, and these structures can be used in high frequency applications.