Biquadratic Transfer Research Articles

Active switched capacitor filter realization for a biquadratic voltage transfer function

Using signal-flow graphs, a general synthesis method is given for the realization of a biquadratic voltage transfer function in the z-domain by active switched capacitor networks using only biphased switches, capacitors and operational amplifiers.

An Active Biquadratic Building Block Without External Capacitors

A new configuration requiring no external capacitors in the realization of the biquadratic voltage transfer function is developed. The proposed network contains resistors and two operational amplifiers represented by the one-pole roll-off model. It has very low sensitivities with respect to all passive and active parameters, and is suitable for medium- Q high-frequency applications. Laboratory experiments confirm the validity of the theory and demonstrate the versatility of the circuit as the biquadratic building block.

A Novel Active Realization of a Class of Biquadratic RC Transfer Functions

A simple and straightforward procedure for active realization of a class of biquadratic RC voltage transfer functions with minimum number of passive elements, minimum active sensitivity and minimal spread in element values is given.

An active R filter using CMOS transistor arrays

A versatile state variable active R filter is described, which uses only resistors and CMOS transistor arrays as the circuit elements. The CMOS array can be used to produce either an integrator or an inverting amplifier depending on the power supply voltage. The design equations are very simple and with some modifications, the filter can be used to realize any biquadratic voltage transfer function in a straightforward manner.

Alternate State Space Realization of Biquadratic Voltage Transfer Function Using Grounded Capacitors

A state variable approach is proposed for the realization of a biquadratic voltage transfer function. It uses equal valued earthed capacitors. The first order all pass filter used as an elemental block in this circuit is shown to have a superior performance than Deboo's integrator. Subsequent analysis takes into account finite gain and finite bandwidth of the practical operational amplifiers used. Experimental results are presented for a bandpass filter that covers a wide range of Q factor and resonant frequency values. They agree well with the computed values obtained using numerical techniques.

Simplified Approach to the Minimal Realizations of Non-minimum Phase Biquadratic RC Voltage Transfer Functions

A simple method of deriving minimal realizations of all possible zero locations of a non-minimum phase biquadratic RC voltage transfer function is gives.

State space synthesis of the biquadratic voltage transfer function using grounded capacitors

Stale variable synthesis of a biquadratic voltage transfer function using equal-valued grounded capacitors is presented. Numerator coefficients of transfer function, pole-pair resonant frequency and Q factor can each be independently controlled. A wider range of Q values is possible than in other schemes. Supporting experimental results are included.

Comments on "Minimal Realizations of Nonminimum Phase Biquadratic RC Voltage Transfer Functions

Comments on "Minimal Realizations of Nonminimum Phase Biquadratic RC Voltage Transfer Functions

Flexible active filter design using three-operational amplifiers

Active circuits containing three-operational amplifiers are presented from which various filter transfer functions can be easily obtained via open-circuiting appropriate passive elements. Any element value of the circuit depends only on a single coefficient of the biquadratic voltage transfer function realized.

Synthesis of RC networks containing operational amplifiers using flowgraph techniques

By using Coates's flowgraphs, a new approach to operational-amplifier?RC-network synthesis is given. The general biquadratic voltage transfer function is realised by this method. Furthermore, it is shown by an illustrative example that obtaining any other desirable transfer function directly from this realisation is possible.

Linear system simulation using differential-input dual-output amplifiers†

An RC active network, with grounded capacitances incorporating two differential-input dual-output operational amplifiers is presented for the realization of a biquadratic voltage ratio transfer function. Two examples illustrating the procedure are worked and the sensitivity figures are shown to be low by calculation.

Active realization of nonminimum phase RC transfer functions

A method of realizing transfer functions having poles on the negative real axis and zeros anywhere in the s plane is presented. The circuit uses an inverting amplifier of maximum gain unity and a minimum phase RC network in a dual-input unbalanced configuration. The theory is illustrated by two examples of biquadratic nonminimum phase RC transfer functions, of which one is an all-pass type. The sensitivity of the realizations to active and passive element variations is also discussed.

Design formulas for active RC filters using operational-amplifier biquad

Complete design formulas for realising any biquadratic voltage transfer function are given. The configuration uses ten or fewer resistors, two capacitors and four single-ended operational amplifiers. The realisation achieves extremely low sensitivity and can readily be used in realising stable high Q factor active filters up to 100kHz.