Third order quadrature oscillator and its application using CDBA

Third‐order quadrature sinusoidal oscillators with fully uncoupled tuning laws using only two CFOAs and grounded capacitors

“…From Table 1, it is seen that none of the ABBs in the oscillators of the quoted references are available as commercial ICs yet. Moreover, the circuits compared in Table 1 suffer from one or more of the following drawbacks: (i) employment of all ungrounded capacitors, [37][38][39][40] (ii) nonavailability of independent control of CO and FO both, [37][38][39][40] and (iii) nonavailability of both outputs from low output impedance nodes. [24][25][26][27][28][29][30][31][32][33][34] A careful inspection of all the previously known CFOA-based TOQSO circuits of [20][21][22][23] reveals that they require three CFOAs and 4/5 resistors but do not provide fully uncoupled control of CO and FO.…”

“…Of late, there also has been considerable research effort on third‐order oscillators since they are expected to provide high‐quality waveforms with low harmonic distortion 2,3 . Consequently, many authors have proposed third‐order quadrature oscillators using a variety of active building blocks (ABB) such as op‐amps, operational transconductance amplifiers (OTA), current differencing transconductance amplifiers (CDTA), multiple‐input second‐generation current conveyors (MOCCII), current differencing buffered amplifiers (CDBA), operational transresistance amplifiers (OTRA), voltage differencing buffered amplifiers (VDBA), differential voltage current conveyors (DVCC), differential difference current conveyors (DDCC), current controlled current conveyors (CCCII), voltage differencing transconductance amplifiers (VDTA), multiple‐output current controlled current conveyor transconductance amplifiers (MOCCCCTA), modified current following transconductance amplifiers (MCFTA), current‐controlled current conveyor transconductance amplifiers (CCCCTA), differential voltage current conveyor transconductance amplifiers (DVCCTA), voltage differencing inverting buffered amplifiers (VDIBA), fully differential second‐generation current conveyors (FDCCII), voltage differencing current conveyors (VDCC), and many more 4–51 …”

Systematic realization of low‐frequency third‐order sinusoidal oscillators

“…9 In open literature, various approaches have been used to realize third-order sinusoidal oscillator (TOSO) circuits. [10][11][12][13][14][15][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] The reported TOSO circuits have been designed using one of the following approaches:…”

“…• A cascade connection of second-order low-pass filter and an inverting integrator in a loop with unity feedback. [10][11][12][13][14][15][16][17][18][19][20][21][22][23]50 • A cascade connection of second-order high-pass filter with noninverting differentiator in a loop. 16,17,50 • A combination of an inverting lossy integrator with two lossless noninverting integrators in a loop.…”

“…[10][11][12][13][14][15][16][17][18][19][20][21][22][23]50 • A cascade connection of second-order high-pass filter with noninverting differentiator in a loop. 16,17,50 • A combination of an inverting lossy integrator with two lossless noninverting integrators in a loop. 15,[24][25][26] • A cascade connection of two noninverting lossy integrators and one lossless inverting integrator with unity feedback.…”