purpose: e is a commonly use letter for illiterates or those who could not read english to measure visual acuity. the e chart is the mainly used charts in iran. however, they do not have the standards. they are in different format, fixed for 6 meter test, with or without lighting, with unequal number of letters in each line and different contrasts. as a result, there is an essential need for a ...

We used a spatially broadband optical parametric amplifier for image amplification. In the phasesensitive configuration of the amplifier, we observed noiseless amplification of input images. For a gain of 2.5, we measured noise-figure values of (0.2 6 0.6) and (0.4 6 0.5) dB, respectively, for two amplifiers of different lengths. These experimental values agree with theory (for an ideal noisele...

In this paper, the data predistorter with memory used to minimize total power consumption due to amplifier nonlinearity in single power mode quadrature amplitude modulation(QAM) systems is investigated. The design of the data predistorter (DP) with memory is independent of the operating optimality criterion but depends upon the operating point of amplifier nonlinearity. The more useful choice o...

an active antenna for transmitter application in s frequency band is designed and analyzed using harmonic balance technique which is based on the nonlinear model of active devices. in this active antenna, the amplifier is integrated with the radiator which is a rectangular patch antenna. this patch antenna is analyzed employing full-wave momentum method. by applying nonlinear model of transisto...

This paper presents a design of the transimpedance amplifier using 0.35μm CMOS technology. In the proposed transimpedance amplifier, feedback resistor RF of conventional transimpedance amplifier has been replaced by NMOS transistor as an active feedback resistor. This circuit operates at 3.3V power supply voltage and for a photocurrent of 0.5μA.The proposed transimpedance amplifier having low n...

This paper presents the design and simulation of Low Noise Amplifier (LNA) in a 0.18μm CMOS technology. The LNA function is to amplify extremely low noise amplifier without adding noise and preserving required signal to noise ratio. Cadence design tool Spectre_RF is used to design and simulation based on resistors, inductors, capacitors and transistors. Power constrained methodology is used for...

Simple instrumentation amplifier circuit diagram using opamp. Equation The addition of input buffer stages makes it easy to match (impedance matching) the amplifier with the preceding stage. A single LM324 op amp Ic is a good choice. feedback differential amplifier. The LMH6550 has the an IF amplifier in high-performance communications. • Video Over TwistedSingle End to Differential Converter a...

Fig.2 Amplifier under test. Amplifiers can operate in classes A, B, AB, C, D, E and F [2]. We tested class A amplifier made by „Microwave Power Devices“, Model: LWA 4690-1/1837, based on bipolar devices (Fig.2). Usually, 1dB compression point, gain and two-tone third-order intercept point are measured as the amplifier figure of merit. As specified by manufacturer, the frequency range of the amp...

In this paper we present an ultra low-voltage (ULV) floating-gate (FG) transconductance amplifier The amplifier is can operate at supply voltages down to 0.3V in a standard digital double poly CMOS process . The amplifier consists of three subcircuits, the single input analog FG inverter, the additive (double input) analog FG inverter with tunable gain and a FG digital inverter. Preliminary mea...

The efficiency optimization of a feedforward low distortion power amplifier is presented. Based on the principle of distortion compensation, the main amplifier output power, that of subamplifier, and amplifier efficiency have been accurately derived. In the present analysis, the coupling coefficient of main signal and distortion paths is selected as the optimization parameter because it may ess...