We present a concept of "active material" with variable acoustic properties, being constituted of an electroacoustic transducer which acoustic impedance can be changed by an active mean. Among the different ways to obtain variable acoustic properties on an electroacoustic transducer's voicing face is the shunting of the transducer's electrical input. With such shunt devices, the acoustic impeda...

A Microcontroller based digital pH meter was designed and developed to measure the value of pH (acidity or alkalinity) for any type of solution. Two op-amps of high input impedance and low output impedance were used to design the pH meter: one is used as a buffer and the other as a summing amplifier. The output of the summing amplifier is connected to the microcontroller as an input. The pH val...

What is a Low-Noise Amplifier? Digital signal processing (DSP) systems require interfaces to the analog world. The first amplification stage in a radio receiver is typically the tuned low-noise amplifier (LNA), which provides enough amplification to the input signal to make further signal processing insensitive to noise. Although the primary goal in LNA design is to minimize the system noise fi...

How big should the conductors be? The required size (or gauge) of the conductors depends on three factors: (1) the load impedance; (2) the length of cable required; and (3) the amount of power loss that can be tolerated. Each of these involves relationships between voltage (volts), resistance (ohms), current (amperes) and power (watts). These relationships are defined with Ohm’s Law. The job of...

Previously reported wideband CMOS low-noise amplifiers (LNAs) have difficulty in achieving both wideband input impedance matching and low noise performance at low power consumption and low supply voltage. We present a transformer noise-canceling wideband CMOS LNA based on a common-gate topology. The transformer, composed of the input and shunt-peaking inductors, partly cancels the noise origina...

Formulas for the noise figure, and the minimum uoisefigure of a multi-link distributed amplifier have been developed. In addition, a relatively simple approximation formula has been devised that predicts the minimum noise figure of a practicaf amplifier design with good accuracy np to frequencies of 9 GHz. Finafly, after the dependence of the noise characteristics on the circnit parameters is d...

New cell phone designs demand small form factor while maintaining audio sound-pressure level. Speakers have typically been the component that limits the thinness of the design. New developments in ceramic, or piezoelectric, speakers have opened the door for new sleek designs. Due to the capacitive nature of these ceramic speakers, special considerations need to be taken into account when choosi...

In this paper, a novel circuit realizing the square rooting function in current-mode is presented. The circuit makes use of a recently proposed active building block (ABB), namely the current controlled current differencing transconductance amplifier (CCCDTA). The circuit offers the following advantages: (i) a complete current-mode circuit makes it suitable for current-mode signal processing ap...

ETRI Journal, Volume 29, Number 5, October 2007 ABSTRACT⎯An ultra-wideband low-noise amplifier is proposed with operation up to 8.2 GHz. The amplifier is fabricated with a 0.18-μm CMOS process and adopts a twostage cascode architecture and a simplified Chebyshev filter for high gain, wide band, input-impedance matching, and low noise. The gain of 19.2 dB and minimum noise figure of 3.3 dB are m...