A bandpass filter using the operational amplifier pole

The operational amplifier rolloff characteristics and a single capacitor are used for obtaining an inverting bandpass function. The filter performance depends on the gain-bandwidth product of the operational amplifier. Experimental results are included. The amplifier rolloff characteristics can be utilised in deriving transfer functions. The resulting filters have an extended frequency range of operation and a reduced number of external capacitors.     

A bandpass filter using the operational amplifier pole

The pole of an operational amplifier and a grounded capacitor are used for obtaining a high Q bandpass function. The utilization of the pole of the operational amplifier enables the extension of its useful frequency range. The gain and the bandwidth of the operational amplifier are the primary factors determining the filter performance. The experimental results of a low-sensitivity filter circuit are presented. The circuit is suitable for integration.     

A high-Q temperature insensitive bandpass filter using the operational amplifier pole

A bandpass filter using only two resistors and two operational amplifiers is suggested. The circuit has a Q equal to the ratio of the ressistors. While Q and gain are insensitive to temperature variations, the variations in center frequency is minimized uing a compensation scheme.     

A novel bandpass filter using the amplifier pole

A new bandpass filter using the operational-amplifier pole and a single external capacitor has been described. It has been shown that the circuit can realize infinite pole-frequency Q product. The applicability of the circuit for realizing bandpass filters and oscillators has been investigated.     

Current-mode lowpass and bandpass filters using the operational amplifier pole

This paper proposes a circuit configuration for realizing current-mode lowpass and bandpass filters using the operational amplifier (op.-amp.) pole. The circuit simultaneously realizes lowpass and bandpass transfer functions using an op.-amp., three resistors and a capacitor. The effects of the paras tic poles (i.e. second and third poles) of the op.-amp. on the gain of a lowpass filter are also presented. Since the circuit uses the op.-amp. pole, it is suitable for high frequency operation.     

Flexible active filter design using operational amplifier pole

A synthesis procedure for generating second-order active filters using the operational amplifier pole and a single external capacitor is given. The proposed method is based on drawing the signal-flow graph from the given transfer function and obtaining the circuit realization from the graph.     

Brief communication Current-mode highpass and bandpass filters using the operational amplifier pole

A circuit configuration for realizing current-mode highpass and bandpass filters using the operational amplifier (op.-amp.) pole is proposed. The circuit simultaneously realizes highpass and bandpass transfer functions using an op.-amp., two resistors and a capacitor. The effects of parastic poles (i.e. second and third poles) of the op.-amp. are also presented. Since the circuit uses an op.-amp. pole, it is suitable for high frequency operation.     

Current-mode highpass, bandpass and lowpass filters using the operational amplifier pole

The use of the Operational Amplifier (OA) pole has received much attention for its potential advantages of miniaturization, ease of design and high frequency performance. This paper proposes a novel circuit configuration for realizing current-mode filters using the OA pole. The circuit realizes simultaneously highpass, bandpass and lowpass transfer functions. Since the circuit uses the OA pole, it is suitable for high frequency operation.     

High-selectivity grounded capacitor bandpass/low-pass filters using the operational amplifier pole

Using the single-pole model of the operational amplifier (OA) a grounded capacitor network has been analyzed to yield either a bandpass or a low-pass function by adjustment of a single resistor. The bandpass/low-pass filters are suitable for high selectivity applications at extended frequency ranges with the advantage of independent adjustment of pole-frequency, pole-Q factor, and midband/passband transmission gain. The network has low sensitivity to all the circuit parameters. The experimental results are quite in agreement with the analysis.     

Versatile voltage-mode universal biquad filter using the operational amplifier pole

A new multifunction voltage-mode biquad filter topology having three inputs and one output is described. The filter consists of a single operational amplifier (OA), a single capacitor, and two resistors and supports LP, BP, HP, AP and Notch filtering signals from the same topology, without requiring additional components besides being devoid of component matching constraints. The filter uses OA pole and has thereby acquired suitability for extended frequency operation. The natural angular frequency ω₀ and the Q can be separately tuned. The circuit has low sensitivity figures. PSPICE simulation results are employed to verify the circuit performance.     

A new independently adjustable filter using the operational amplifier pole

A new second-order lowpass active filter, based on the single pole roll-off characteristics of the operational amplifier, with only one operational amplitier and a single external capacitor is presented. Independent control of centre frequency, frequency selectivity and passband gain by a single resistor is possible with this design. The filter has low sensitivity to all circuit active and passive parameters and is suitable for low-medium-high Q factor operations over a wide range of frequencies. The filter is suitable for integration.     

Grounded-capacitor bandpass filter using the operational-amplifier pole

A configuration for realising a 2nd-order bandpass filter based on the single-pole roll-off characteristics of the operational amplifier with a single grounded external capacitor is presented. The filter has low sensitivity to all the circuit parameters. Experimental results verify its suitability in high-frequency applications with moderately high selectivity. Independent control of centre frequency, frequency selectivity and midband gain is possible.     

New Q enhancement technique of low pole frequency bandpass filter using single-ended operational amplifiers

A new bandpass filter with low pole frequency (ω_p) and high selectivity (Q) derived from state variable technique is described. Design equations and sensitivity figures are also presented.     

A tunable filter using amplifier pole

A circuit consisting of two periodically operated switches, potentiometers, resistors, and compensated operational amplifiers, but not containing external capacitors, is proposed for the realization of a second-order bandpass and low-pass filter. The filter is electronically tunable and the natural frequency of the filter varies linearly with the width of the pulses controlling the FET switches.     

Low-pass and notch filters using the operational amplifier pole

Low-pass and notch filters using the pole of the operational amplifier and a single external capacitor have been described. The limitations of these at low pole frequencies are also discussed.     

RC active bandpass filter synthesis using a voltage amplifier

An active RC filter employing a voltage amplifier as the active element has been chosen. The root sensitivity of the filter with respect to change in the gain of the amplifier has been calculated and minimized to establish a method of synthesis for achieving stability of center frequency and bandwidth.     

Active all-pass filter using a differential operational amplifier

A circuit is presented for a first-order active all-pass filter using a single differential operational amplifier. The form of the transfer function is T(p) = (1 ? p)/(1 + p).     

Switched-capacitor simulation of floating inductors using the operational amplifier pole

An active switched-capacitor realization of a floating inductor using the operational amplifier pole is described. The circuit uses two operational amplifiers, two capacitors, and two toggle switches.     

Comments on `A novel bandpass filter using the amplifier pole'

In a recent correspondence by Anandamohan (see ibid., vol.SC-14, p.649, 1979), the author fails to see any new circuit. The author suggests that the proposed circuit is a particular case of a circuit reported earlier by Mitra and Aatre (1976).