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This paper presents a novel voltage-controlled current-mode second-order multifunction frequency filter employing CFTAs (Current Follower Transconductance Amplifier) and PCAs (Programmable Current Amplifier). Possible internal bipolar structure of the CFI'A+/- element and the realization of the PCA using current multiplier EL2082 and secondgeneration current conveyor CCII+/- are presented. The proposed filter structure enables realizing the low- (LP), band- (BP), high-pass (HP) and the band-stop (BS) responses. The properties of the proposed filter were verified using PSPICE simulations. [ABSTRACT FROM AUTHOR]

In this article, a new voltage-mode second-order universal frequency filter and sinusoidal oscillator using only single differential-input buffered and transconductance amplifier (DBTA) is presented. The proposed voltage-mode filter structure using single DBTA and four passive elements can provide all standard filter functions, i.e. low-, band-, high-pass, band-stop, and all-pass without changing the circuit topology and enables independent control of the quality factor Q using single passive element. The circuit requires the minimal number of active and passive elements with no conditions for component matching. By slight modification of the proposed filter structure, the new DBTA-based sinusoidal oscillator is easily obtained. The oscillation condition and the oscillation frequency are independently adjustable by different virtually grounded passive elements. The proposed sinusoidal oscillator employs only grounded capacitors. The passive and active sensitivities of all the proposed circuit configurations are low. PSPICE simulations using a BJT realisation of DBTA and experimental results based on commercially available amplifiers OPA860 and MAX436 are included, which prove the workability of the proposed circuits. [ABSTRACT FROM AUTHOR]