Patent ID: 8896371

Claim:
A reconfigurable high-order integrated circuit filter, comprising: an electronic circuit including a cascade of second generation current conveyers (CCIIs), first and last CCIIs of the cascade each having an X input, a Y input, and two positive outputs, each CCII disposed in the cascade between the first CCII and the last CCII having an X input, a Y input, and three positive outputs; first feedback circuitry defined by connections from a first of the three positive outputs of the each CCII disposed in the cascade between the first CCII and the last CCII to the X input of the first CCII, the first feedback circuitry also including a connection from a first of the two positive outputs of the last CCII to the X input of the first CCII; a corresponding external feedback current division network (CDN) disposed in-line with each of the connections to the X input of the first CCII; first positive output of the first CCII connected to the Y input of a second CCII of the cascade; for each of the CCIIs disposed between the first and last CCII, a second positive output connected to the Y input of a subsequent stage CCII of the cascade; for each of the second positive output connections to the Y input of the subsequent stage CCII, a corresponding capacitor connected therefrom to virtual ground; for each of the CCIIs subsequent to the first CCII, a corresponding resistor connected from the subsequent CCII X input to the virtual ground; a final output CCII; feedforward circuitry defined by a connection from a second positive output of the first CCII to an X input of the final output CCII and connections from a third of the three positive outputs of the CCIIs disposed between the first and the last CCII to the X input of the final output CCII; a corresponding external feedforward CDN disposed in-line with each of the feedforward circuitry connections to the X input of the final output CCII; and wherein each of the external feedback CDNs has a control input accepting a β f filter coefficient control signal unique to the external feedback CDN, each of the external feedforward CDNs has a control input accepting a β g filter coefficient control signal unique to the external feedforward CDN thereby controlling a transfer function of the reconfigurable high-order integrated circuit filter characterized by the relation, i n ⁡ ( s ) i s ⁡ ( s ) = s n ⁢ β gn s n + ∑ i = 0 n - 1 ⁢ ⁢ β fi ⁢ s i ⁢ ∏ j = i n - 1 ⁢ ⁢ 1 C j + 1 ⁢ R j , where i n (s) is the complex current at the n th stage of the cascade, i s (s) is the input complex current, β gn is the transfer function numerator coefficient parameter, β fi is the transfer function denominator coefficient parameter, C j+1 is the j+1 th capacitor associated with the j+1 th stage CCII of the cascade, R j is the j th resistor associated with the j th stage CCII of the cascade, and s is a complex frequency domain representation of the reconfigurable high-order integrated circuit filter.