Multiphase sinusoidal oscillator using the CFOA pole

Abstract

A multiphase sinusoidal oscillator using the parasitic poles of current feedback operational amplifiers (CFOAs) is presented. The oscillator can generate n signals which are equal in amplitude and equally spaced in phase. The oscillator using the parasitic poles of CFOAs is suitable for high frequency applications and monolithic IC fabrication. The effects caused by the nonlinearity of the CFOA on the oscillation frequency and condition have been analysed. Experimental results show that a three-phase sinusoidal oscillator has a wide operating range from 10 kHz to 10 MHz and a large output voltage swing up to 7 V peak to peak while using f 5 V power supply. The total harmonic distortion (THD) of each oscillation frequency is dominated by its third harmonic component which is at least 33dB down from its fundamental. Papa 1682G (ElO), first received 17th March and in revised form 8th

Tunable active-R oscillator using a CFA

“…The typical values of the internal components [2,7,8] of the AD-844 element are R y = 1/G y = 2 M.ohm, R z = 1/G z = 5 M.ohm, C y = 3 pF and C z = 7 pF. For generation in the MHz range, capacitors C y,z are to be tuned by resistors in KΩ scale.…”

“…Some active-R sinusoid oscillator circuits using CFAs were proposed earlier [7,8,9,10]. The CFA pole was utilised for multiphase sinewave generation in Ref.…”

“…The CFA pole was utilised for multiphase sinewave generation in Ref. [7] where the realisability condition and fo-tuning law are interactive. Liu et.…”

Electronically Controllable Current-Mode Multiphase Sinusoidal Oscillator for Biomedical Tissue Measurement Systems

“…Several realizations of current-mode MSOs using different active building blocks are available in the literature. These include realizations using current follower (CF) [8], CCCII [9]- [11], CDTA [12]- [14], CDBA [15], CFOA [16], and CCCCTA [17] and CCCDTA [18], [19]. The CF-based MSO in [8] requires two current followers, one floating resistor, and one floating capacitor for each phase and thus the circuit is not suitable for monolithic integration.…”

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