This invention relates to 2° order biquad/universal continuous time IF analog active filters for telecommunications and active full self-compensation techniques to improve the frequency range, the stability and/or the selectivity of the filters with a very low, or as if zero, cost. These techniques are the only ones in the world that(fully) erase the parasitic poles using a single resistor or an additional operational amplifier with a functionally filtering output; this means that in several applications the additional manufacturing cost is zero and, however, very low.
This is the key principle which makes very evaluable this patent (37 claims, of which 9 independent, and 38 drawings).

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