Universal three input and one output current-mode filter withoutexternal passive elements

A new current-mode universal filter is proposed. The filter uses only operational amplifiers and operational transconductance amplifiers (OTAs) and can realise lowpass, highpass, bandpass, notch and allpass responses without changing circuit topology. The parameters 0, 0/Q0, and the gain can be electronically tuned by adjusting the bias currents of the OTAs. The proposed circuit has low sensitivit

"A current conveyor-based relaxation oscillator as a versatile electronic interface for capacitive and resistive sensors"

A new electronic interface circuit is presented. The circuit is built around a single plus-type second-generation current conveyor (CCII+) and can be used with resistive, capacitive and resistive-capacitive sensors. Experimental results are provided

"Comment: Nonlinear SNR amplification of harmonic signal in noise"

This comment relates to a recently published Letter, which computes the signal-to-noise ratio (SNR) of a harmonic signal in additive noise after transformation by an arbitrary memoryless nonlinearity. According to the authors, with a simple saturating nonlinearity having direct electronic implementation, an amplification of the SNR can be obtained. It is shown here that this computation and the resulting conclusion are not new

"Analogue CMOS, low-voltage, current-mode implementation of digital logic gates"

In this letter a new technique is introduced for implementing the basic logic functions using analog current-mode techniques. By expanding the logic functions in power series expressions, and using summers and multipliers, realization of the basic logic functions is simplified. Since no transistors are working in saturation, the problem of fan-out is alleviated. To illustrate the proposed technique, a circuit for simultaneous realization of the logic functions NOT, OR, NAND and XOR is considered. SPICE simulation results, obtained with 3V supply, are included

"A low-cost dual-slope triangular/square wave generator"

A new dual-slope triangular/square wave generator is presented. The circuit uses few active and passive components and can be easily integrated. Experimental results obtained from a breadboard implementation, using discrete transistors, show that by using a grounded resistor the frequency of oscillation can be tuned in the range 1.7 kHz-3.5 kHz without disturbing the slopes the positive-going and the negative-going edges of the triangular wave

"Large signal analysis of the dual-parallel electroabsorption modulator"

Large signal analysis of the dual-parallel electroabsorption modulator driven by a mutisinusoidal RF signal is presented. The special case of a two-tone equal-amplitude RF signal is considered in detail, and the results are compared with previously published result

A translinear current-mode programmable analog exponential function synthesizer

A new circuit configuration is presented for synthesis of analog exponential functions. The proposed circuit is based on approximating the exponential function using rational functions. The circuit is flexible and can synthesize any exponential function, to any degree of accuracy, once its rational-function approximation is obtained. The proposed circuit uses only bipolar transistors and current-sources and is, therefore, very attractive for integration. SPICE simulation results are included

Large Signal Analysis of the Infrared Semiconductor Mercury-Cadmium-Telluride Detectors

A mathematical model for the relationship between the output voltage and incident radiation of the infrared semiconductor mercury-cadmium-telluride (MCT) detector is presented. The model, basically a sine-series function, can easily yield closedform expressions for the harmonic and intermodulation performance of the MCT detector with large-amplitude multisinusoidal incident radiation. The special case of two-tone equalamplitude incident radiation is considered in detail. The results show that the second-order harmonic and intermodulation products are always higher than the third-order components. Moreover, the results show that the second-order intermodulation is always dominant

Large Signal Analysis of Wideband Nonlinear Amplifiers with Third-Order Intermodulation and Second-Harmonic Injection

Large signal analysis of a wideband nonlinear amplifier excited by a multisinusoidal signal is pre-sented. The special case of two equal-amplitude sinusoids and their injected second-harmonic and third-order intermodulation component is considered in detail and the results are compared, whenever possible, with pre-viously published experimental results

Carrier and intermodulation performance of limiters excited bymulticarriers

A general formula, using a Fourier-series representation, is derived for the input-output characteristic of ideal hard limiters, biased hard limiters and biased soft limiters. Using this formula one can obtain an expression, involving Bessel functions for calculating the amplitudes of the output products of a limiter excited by a multicarrier signal plus Gaussian noise. In contrast with previously published results, the implementation of the present expression requires the computation of functions that are available in most mathematical-library subroutines and can even be implemented by using programmable pocket calculators. Results obtained by using the present expression are in excellent agreement with the previously published results. Additionally, the expression is used to generate a soft- and a hard-limiter signal-suppression database for the case in which a single large carrier and a number of equal-power small carriers exist in a noisy environmen