Reconfigurable high-order integrated circuit filters

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 βf filter coefficient control signal unique to the external feedback CDN, each of the external feedforward CDNs has a control input accepting a βg 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 in(s) is the complex current at the nth stage of the cascade, is(s) is the input complex current, βgn is the transfer function numerator coefficient parameter, βfi is the transfer function denominator coefficient parameter, Cj+1 is the j+1th capacitor associated with the j+1th stage CCII of the cascade, Rj is the jth resistor associated with the jth stage CCII of the cascade, and s is a complex frequency domain representation of the reconfigurable high-order integrated circuit filter.