Simple Compensation Circuit Research Articles

A Probabilistic Prediction-Based Fixed-Width Booth Multiplier for Approximate Computing

In order to gain substantial circuit performance improvement in terms of power, speed and area cost, approximate computing is ideally applied in many error-resilient DSP and multimedia applications by relaxing the requirements of exact computation. Fixed-width multipliers are intensively used in those applications, which makes them a good demonstration for approximation through dynamic range reduction. In this paper, a probabilistic prediction based fixed-width Booth multiplier has been proposed. The error compensation function is derived from the probabilistic analysis on the partial products obtained from Booth encoding. By slightly modifying the partial product array with dedicated partitioning, a simple compensation circuit is thus formulated. Compared with the previous works, the proposed design exhibits the best performance-accuracy tradeoff. It achieves at least 27% reduction on the area-energy-delay-error product compared with the other multipliers among various operand lengths. Additionally, the evaluation on 2-Dimensional discrete cosine transform (DCT) circuits indicates that our proposed fixed-width Booth multiplier is applicable for lossy applications with a considerable reduction on hardware expenses and power dissipation while maintaining decent output quality.

Low Cost Ferroelectric Loop Study Set up With New and Simple Compensation Circuit: Operated at Variable Frequencies

We report a cost effective high power (500 W) ferroelectric loop study set up. It has a new type of simple compensation circuit for continuous compensation of stray linear capacitance and large value resistive losses of the sample. It can be operated at continuous variable frequency modes to observe the loop structure at different frequencies. The proposed system has a drive voltage of 8400 V peak to peak and can be modified to higher voltage and higher frequencies. Instead of a loop plotter, it has a data saving facility for binary or ASCII files such that further processing of the data by computer software such as origin, excel etc can be achieved. This high power set up is suitable for a highly lossy sample. Moreover, uncompensated and compensated loop studies and time dependent loop growth observation for ceramic BaTiO3 are discussed here in.

An on-chip temperature compensation circuit for an InGaP/GaAs HBT RF power amplifier

A new on-chip temperature compensation circuit for a GaAs-based HBT RF amplifier applied to wireless communication is presented. The simple compensation circuit is composed of one GaAs HBT and five resistors with various values, which allow the power amplifier to achieve better thermal characteristics with a little degradation in performance. It effectively compensates for the temperature variation of the gain and the output power of the power amplifier by regulating the base quiescent bias current. The temperature compensation circuit is applied to a 3-stage integrated power amplifier for wireless communication applications, which results in an improvement in the gain variation from 4.0 to 1.1 dB in the temperature range between −20 and +80 °C.

High-Accuracy Fixed-Width Modified Booth Multipliers for Lossy Applications

The fixed-width multiplier is attractive to many multimedia and digital signal processing systems which are desirable to maintain a fixed format and allow a little accuracy loss to output data. This paper presents the design of high-accuracy fixed-width modified Booth multipliers. To reduce the truncation error, we first slightly modify the partial product matrix of Booth multiplication and then derive an effective error compensation function that makes the error distribution be more symmetric to and centralized in the error equal to zero, leading the fixed-width modified Booth multiplier to very small mean and mean-square errors. In addition, a simple compensation circuit mainly composed of the simplified sorting network is also proposed. Compared to the previous circuits, the proposed error compensation circuit can achieve a tiny mean error and a significant reduction in mean-square error (e.g., at least 12.3% reduction for the 16-bit fixed-width multiplier) while maintaining the approximate hardware overhead. Furthermore, experimental results on two real-life applications also demonstrate that the proposed fixed-width multipliers can improve the average peak signal-to-noise ratio of output images by at least 2.0 dB and 1.1 dB, respectively.

Very high QE HPDs with a GaAsP photocathode for the MAGIC telescope project

Hybrid photon detectors are one of the few low light level sensors that can provide an excellent single and multiple photoelectron amplitude resolution. The recently developed hybrid photon detectors for the Major Atmospheric Gamma-Imaging Cherenkov (MAGIC) telescope project with an 18-mm-diameter GaAsP photocathode (the Hamamatsu R9792U-40) have a peak quantum efficiency of more than 50% and a pulse width of ∼ 2.3 ns . In addition, the afterpulsing rate of these tubes is ∼ 300 times lower compared to that of conventional photomultiplier tubes. Photocathode aging measurements showed lifetimes of more than 10 years under standard operating conditions of Cherenkov Telescopes. The temperature dependence of the avalanche gain can be reduced to the same level of a photomultiplier by a simple compensation circuit. Here we report on the recent progress with the above-mentioned hybrid photon detectors.

A Highly Accurate Saturable Reactor Type Constant Current Power Supply Using a Simple Compensation Circuit

This paper describes analytical and experimental results for a new highly accurate saturable reactor type power supply using a simple compensation circuit. A simple compensation circuit consisting of a resistor and a diode can produce a constant current in a power supply with very high accuracy. The related analytical and experimental results demonstrate that this compensation circuit eliminates the deviation in output current due to the magnetization characteristics of the saturable reactor. The output current fluctuations of this power supply, which uses a core with a relatively smooth characteristic such as a ferrite coref are only half those of conventional power supplies.

可飽和リアクトル形定電流電源の簡易補償回路による高精度化

This paper describes analytical and experimental results for a new highly accurate saturable reactor type power supply using a simple compensation circuit. A simple compensation circuit consisting of a resistor and a diode can produce a constant current in a power supply with very high accuracy. The related analytical and experimental results demonstrate that this compensation circuit eliminates the deviation in output current due to the magnetization characteristics of the saturable reactor. The output current fluctuations of this power supply, which uses a core with a relatively smooth characteristic such as a ferrite coref are only half those of conventional power supplies.

The temperature dispersion of the quarter-wave voltage of KD2xH2(1-x)PO4and a simple compensation circuit

The temperature dispersion of the quarter-wave voltage has been studied for four crystals of KD2xH2(1-x)PO4 with x=0.500, 0.885, 0.935 and 0.985 respectively, in the -120 to 120 degrees C range, at lambda =0.63 mu m and 1.06 mu m. The linear dependence of the static longitudinal quarter-wave voltage, previously reported at low temperatures, was observed up to the high temperature phase transition, and a fairly parallel shift of the Vlambda 4/=f(T) curves, dependent on the degree of deuteration, was confirmed. To avoid this temperature dispersion (and the deuteration dependence) of the quarter-wave voltage being an obstacle to the use of this material in applications where operation in a wide temperature range is required, the authors designed a simple compensation circuit with adjustable slope dV/dT and adjustable voltage limits.

Pirani manometer with linearized response

A fast-reading Pirani manometer with an electronically linearized response for gas pressures between 3×10−4 and 0.5 Torr is described. The time constant of the manometer is 20 msec. Two NTC resistors are used, one for the sensor in the vacuum system and one for the reference at constant pressure. The pressure in the vacuum system is measured by analog computation of the power needed to stabilize the two resistors to equal temperature. By a relatively simple compensation circuit, changes in room temperature within ±10 °C can be eliminated to less than 1 per mille per degree. The manometer is built from inexpensive standard electronic components.

Fluidic control of processes with transportation lag

A brief survey of current means to implement a transportation lag fluıdically is presented and a novel fluidic device, the bubble tube lag simulation, is developed. A fluidic pulse frequency comparator is designed to serve as a summing junction emitting a pulse train whose frequency is equal to the difference in frequency between two input pulse trains. A study is presented of the feasibility of controlling processes containing transportation lag using fluidic devices. A fluidic controller which operates in the pulse frequency modulated mode has been developed, built and tested successfully, and a simple compensation circuit is fabricated. The parameters of the compensator are adjusted to optimize system response.