Electronically tunable immittances with applications to LP, BP, HP filter and VCO implementation. Issue 1 (2nd January 2021)

• Record Type: Journal Article
• Authors: Nandi, R.; Mathur, K.; Venkateswaran, P.
• Is Part Of: International journal of electronics letters. Volume 9:Issue 1(2021)
• Page Start: 65
• Page End: 75
• Publication Date: 2021-01-02
• Subjects: Synthetic inductor/FDNR -- VTCCTA -- MMCC -- linear VCO -- short-circuit natural frequency; Electronics -- Periodicals; Electronics; Periodicals; 621.38105
• DOI: 10.1080/21681724.2019.1672800
• Languages: English
• ISSNs: 2168-1732

Abstract

ABSTRACT: Electronically tunable synthesis of immittances viz., inductor (L) and FDNR (D), using the voltage tunable current conveyor transadmittance amplifier (VTCCTA) block is presented. Design of selective LC and DR type resonators are derived. Subsequently, based on these resonators new VCO implementations, underlying the concept of short-circuit natural-frequency is proposed. According to this concept, second-order resonators yield a pair of imaginary-axis pole-pair; if Q~∞ this is amenable to sinusoid oscillator implementation without necessitating a nominal input stimulus (Vi ~0: short-circuit) to the resonator whereby the oscillation frequency ( fo ) is the natural pole-frequency. To this end, both the LC and DR resonators may be utilised for the VCO design using a multiplication mode current conveyor (MMCC) element, of which the LC type follows a linear tuning law variable by a control voltage (Vd.c.). Experimental results with simulation and hardware-circuit test had been satisfactorily verified using standard commercially available IC-modules. Linear range of f o -variation upto 10 MHz with satisfactory phase noise-margin had been measured.