Iqbal A. Khan

Simple first order all-pass section using a single CCII

A novel first order all-pass section using a single second generation current conveyor is given. In addition the circuit uses two resistors and only one capacitor. The circuit is also realized with a translinear conveyor. The latter circuit uses only one external resistor and a capacitor. The proposed circuits are verified using PSPICE with attractive results.

Novel first order all-pass sections using a single CCIII

Two novel first order voltage-mode all-pass sections using a single third generation current conveyor (CCIII) are given. In addition the first circuit uses three resistors and one capacitor and the second circuit which is derived from the first circuit uses two resistors and one capacitor. A current-mode first order all-pass section requiring one capacitor and one resistor is also proposed. SPICE simulation results are incorporated to verify the theory.

An integrable gm-C quadrature oscillator

An integrable quadrature oscillator circuit is given which uses only transconductance elements and grounded capacitors in its realization. The circuit provides four quadrature outputs of equal magnitude. It uses a low component count and is compatible for monolithic implementation in MOS technology. The simulation results on the quadrature oscillator verify the theory.

On transconductance-C quadrature oscillators

Two circuits of Electronically Tunable Quadrature Oscillators (ETQOs) are given, which only use operational transconductance amplifiers (OTAs) and capacitors. In these circuits, a wide range of linear ƒo-tunability is present with bias voltage/current control of the OTAs. Outputs of equal amplitude, but in quadrature, are available in both the ETQOs. The circuits have a low component count, attractive sensitivities and suitability to implementation in monolithic MOS technology. Experimental results are included in support of the theory.

Tunable OTA-based multiphase sinusoidal oscillators

Using a simple scheme, realisation of some novel multiphase sinusoidal oscillators (MPSOs) employing operational transconductance amplifiers (OTAs) as the active device are considered. These oscillators can provide n signals (n being odd) equal in amplitude as well as equally spaced in phase. Two practical OTA: RC three-phase oscillators have been realised and studied in detail. Their corresponding OTA-C realisations have also been obtained. Both the circuits enjoy low component count, low sensitivity performance and wide range electronic tunability. The OTA-C oscillators are highly suitable for monolithic implementation in MOS-form.

Multifunctional translinear-C current-mode filter

A multifunctional current mode filter using three current controlled conveyors and two grounded capacitors is described. The filter realizes high pass, band pass and low pass second order current transfer functions, and provides independent pole-ω 0, and pole-Q 0 tuning through external current control. The filter also displays low incremental parameter sensitivities. The simulation results on the filter support the theory.

Simple first-order translinear-C current-mode all-pass sections

A first-order translinear-C current-mode (CM) all-pass section (APS) using two current-controlled conveyors (CCCII) and a single capacitor is given. A canonical CM-APS using only one dual-output CCCII and one capacitor is also derived from the proposed configuration. The circuits are analysed for the non-idealities of CCCII and possess attractive sensitivity performance. The proposed circuits are electronically tunable over a wide frequency range. RSPICE simulation results for ac analysis, transient analysis and harmonic distortions are incorporated to verify the theory.

Current Controlled Current Differencing Buffered Amplifier: Implementation and Applications

A new four terminal current-controlled active element is introduced, where parasitic resistances at two current input ports are controlled leading to the definition of current-controlled current differencing buffered amplifier. Bipolar implementation and as application current-mode band-pass filter circuits are proposed. Simulation results using real device parameters are included, which show device bandwidth of 35 MHz, low total harmonic distortions, and tuning over a wide current range.

A simple realisation scheme for OTA-C universal biquadratic filter

A simple scheme for realising four standard second-order voltage transfer functions, viz., low-pass, highpass, bandpass, and band-elimination is presented. It is implemented by using only operational transconductance amplifiers and capacitors to realise two universal biquadratic filters (UBFs), i.e. UBF-I and UBF-II. The UBF-I can also be converted into a sinusoidal oscillator by simply grounding a suitable node. The circuits have the attractive features of wide-range electronic tunability of its pole frequency, bandwidth and pole Q; these can also be programmed digitally. In addition, the filters enjoy excellent sensitivity performance and are suitable for monolithic MOS or Bi-MOS implementation. The effects of non-ideal buffer on the performance of the circuits are studied.

First Order Current Mode Filters and Multiphase Sinusoidal Oscillators Using MOCCIIs

An insensitive current mode versatile first order filter section with single input and multiple outputs is realized. The realization uses two multi outputs current conveyors, only one grounded resistor and one grounded capacitor. The realized current mode section provides low-pass, high-pass and all-pass responses at different outputs without any component matching constraint. The all-pass section is then cascaded with the current mode non-inverting integrator to realize a current mode multiphase sinusoidal oscillator. Thus the realized current mode oscillator provides eight phase sinusoidal outputs with equal magnitudes. The current mode outputs are loaded with same valued resistive load to achieve the eight phase voltage mode sinusoidal outputs with equal magnitudes. All the realization were designed and simulated using PSPICE. The simulation results thus obtained, verify the theory.