Boonying Knobnob

An efficient filter structure for multiplierless Sobel edge detection

This paper presents a multiplierless Sobel edge detection filter structure based on the gradient of Gaussian lowpass filter concept. This concept is same as the idea that used for evaluation of Sobel edge detection kernels. The proposed Sobel edge detection filter structure consists of 4 sets of the so-called lowpass-type 2nd order 1-D DPF (Discrete Pascal Filter) and the filter structure does not need any multipliers, only 14 adders are needed for realization. Consequently, the high efficiency multiplierless Sobel edge detector can be achieved.

Current-Mode Quadrature Oscillator Using Translinear Current Conveyors

A new current-mode quadrature oscillator using two translinear current conveyors and two grounded capacitors is presented. The proposed circuit provides two high output impedance current sources with 900 phase difference. The oscillation frequency can be controlled electronically by adjustting the bias currents of translinear current conveyors. The proposed circuit employs only grounded capacitors and requires no resistors. The use of only grounded capacitors is ideal for integrated circuit implementation. The proposed structure is eminently suitable fabrication in bipolar technology. The theoretical results are verified by PSPICE simulation.

CMOS precision full-wave and half-wave rectifier

This paper presents a new current-mode precision rectifier using CMOS technology. The system comprises a current comparator, current mirrors and diodes that can realize either a half-wave rectifier or a full-wave rectifier into a single system by appropriately adjusting the current gain of a current mirror. The proposed circuit offers low-voltage supply, low-power dissipation and wide bandwidth. The simulation results can be confirmed the operation and performance of the proposed rectifier.

A CMOS Median Filter Circuit Design

This paper proposes a median filter circuit design, which the operations are in current mode and based on CMOS technology. Its structure consists of three main parts, the first part is current average circuit, second part is current absolute value circuit, and third part is current minimum circuit. The results of this circuit can be shown using the PSpice simulation program to demonstrate the performances of this circuit

High-input impedance four-input one-output voltage-mode universal filter using OTAs

This paper presents a new electronically tunable voltage-mode universal filter with four-input one-output using six single-ended operational transconductance amplifiers, two grounded capacitors and two MOS resistors. The proposed circuit can realize of lowpass, bandpass, highpass, bandstop and allpass filters, without component-matching conditions and inverting input signals requirements. The natural frequency and the quality factor can be tuned orthogonally and electronically by adjusting the bias currents. The filter offers the features of high input impedances, low active and passive sensitivities and use of grounded passive components which is ideal for integrated circuit implementation. The workability of the proposed circuit is confirmed using PSPICE simulators.

Voltage-mode SIMO OTA-C universal filter

This paper presents a new voltage-mode single-input multiple-output universal filter employing five simple operational transconductance amplifiers, two grounded capacitors and one grounded resistor. The proposed filter provides low-pass, band-pass and high-pass voltage responses. The natural frequency and the quality factor of the filter can be controlled orthogonally and electronically by adjusting the bias currents of OTAs. The filter characteristics of the proposed circuit are simulated using PSPICE simulations to confirm the presented theory.

Electronically tunable voltage-mode universal filter using simple OTAs

This paper presents a new voltage-mode universal filter with single-input multiple-output employing seven simple CMOS operational transconductance amplifiers, two grounded capacitors and one resistor. The proposed filter can realize lowpass, bandpass, highpass, bandstop and allpass voltage responses from the same topology. The natural frequency (ωo) and the quality factor (Q) can be controlled orthogonally and electronically by adjusting the bias currents of OTAs. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.