Masami Higashimura

Research note Realization of all-pass networks using a current conveyor

Two novel networks for realizing all-pass transfer functions using a single current conveyor and only four passive elements is proposed. The network offers high input impedance.

Novel voltage-mode biquad without external passive elements

This paper introduces a voltage-mode biquad filter using only active devices such as operational amplifiers and operational transconductance amplifiers (OTAs). The circuit configuration is obtained from Soderstrands active-R state variable filter as a prototype. The proposed circuit can realize five different biquad transfer functions, and the circuit characteristics can be electronically tuned by adjusting the transconductance gains of the OTAs. An example is given, together with simulated results by PSPICE. The circuit configuration is very suitable for implementation in both bipolar and CMOS technologies.

Voltage-mode active-only biquad

This paper presents a realization of a voltage-mode active-only biquadratic circuit. The proposed circuit is constructed employing solely operational amplifiers and operational transconductance amplifiers (OTAs). The circuit configuration is obtained from a second-order structure with two integrator loops. The circuit can realize low-pass, band-pass, high-pass, band-stop, low-pass notch, high-pass notch and all-pass transfer functions by suitably choosing the input and output terminals, and the circuit characteristics can be electronically tuned through adjusting the transconductance gains of OTAs. Some examples are given together with simulated results by PSPICE. The circuit configuration is very suitable for implementation in both bipolar or CMOS technologies.

Novel voltage-mode biquad using only active devices

This paper introduces a voltage-mode biquad using only active devices such as operational amplifiers (OAs) and operational transconductance amplifiers (OTAs). The proposed circuit can realize five different biquad transfer functions by choosing the input and output terminals. Also the circuit characteristics can be electronically tuned by adjusting the transconductance gains of the OTAs. An example is given, together with simulated results by PSPICE. The circuit configuration is very suitable for implementation in both bipolar and CMOS technologies.

Versatile voltage-mode active-only biquad with lossless and lossy integrator loop

This paper presents a realization of a voltage-mode active-only biquad using operational amplifiers (OAs) and operational transconductance amplifiers (OTAs). The circuit configuration is obtained from a second-order integrator loop structure with lossless and lossy integrators. The proposed circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by a suitable choice of input and output terminals. The circuit characteristics can be electronically tuned through adjustment of the transconductance gains of the OTAs. An example is given, together with simulated results by PSPICE. The circuit configuration is very suitable for implementation in both bipolar and CMOS technologies.

Realization of all-pass and notch filters using a single current conveyor

A novel network for realizing an all-pass transfer function using a single current conveyor is proposed. The network has high input impedance, this permits to use the networks in cascade without any requiring impedance matching device. By tuning a resistor, the network also realizes a notch filter.

Electronically tunable current-mode active-only biquadratic filter

This paper presents a realization of current-mode active-only filter. The proposed filter is constructed employing operational amplifiers and operational transconductance amplifiers (OTAs). The circuit can realize biquadratic transfer function, and the circuit characteristics can be electronically tuned through adjusting the transconductance gains of the OTAs. An example is given together with simulated result by PSPICE. The circuit configuration is very suitable for implementation in both bipolar or CMOS technologies.

A general class of current-mode high-order OTA-C filters

A current-mode high-order filter configuration is introduced using multiple current output operational transconductance amplifiers OTAs. The circuit has been constructed by employing a current-mode integrator and a proportional block as basic building units. It is shown that the proposed circuit can realize a general class of high-order transfer functions. As an example, a fourth-order filter is given, together with simulated results by PSpice.

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.

Versatile active-only biquad circuits with loss-less and lossy integrators

This paper presents a realization of voltage-mode and current-mode active-only biquad circuits with a two-integrator loop-structure. The circuits are constructed solely with operational amplifiers (OAs) and operational transconductance amplifiers (OTAs). The biquad circuits can realize the multiple circuit transfer functions, and the circuit parameters can be tuned orthogonally through adjusting the transconductance gains of the OTAs. Also, these biquad circuits enjoy very low sensitivities with respect to the circuit active elements. Some examples are given together with simulated results by PSPICE. The circuit configurations are very suitable for implementation on both bipolar and CMOS technologies.