Comparative Assessment on Linearity Test based V2π and Vπ/2 Voltage Variations of Closed Loop IFOG

Interferometric Fiber Optic Gyroscope (IFOG) has to operate in closed loop condition to achieve inertial grade performance. The closed loop system is mainly depends upon the amplitude of the ramp signal (V2π of IOC) and bias (square wave) signal frequency (fbias). The digital phase ramp function is given as feedback to the optical system and makes gyro to null condition. The peak-to-peak amplitude (Vπ/2) of biasing signal is one-fourth of the ramp amplitude (V2π). If there are any variations in the amplitude of the ramp and biasing signals, then it introduces variations in the gyro performance. In this paper, a comparative discussion made in the gyro parameters for three cases: (i) V2π (vary) & Vπ/2 (constant), (ii) Vπ/2 (vary) & V2π (constant) and (iii) both V2π and Vπ/2 are varying simultaneously. The effects on gyroscope are described with the derived values in terms of linearity. From the experimental results, it was observed that the gyro output is very sensitive with respect to V2π variations and obtained the percentage error of 10% in gyro output, but very less effect due to Vπ/2 variations. So, the proper resetting of ramp voltage (V2π) is required to avoid nonlinearities and instabilities in gyro output

DESIGN SPACE EXPLORATION AND OPTIMIZATION OF SUPER SCALAR PROCESSOR

Designing a microprocessor involves determining the optimal microarchitecture for a given objective function and a given set of constraints. Superscalar processing is the latest in along series of innovations aimed at producing ever-faster microprocessors. By exploiting instruction-level parallelism, superscalar processors[1] are capable of executing more than one instruction in a clock cycle.The architectural design of super scalar processor involves a lot of trade off issues when selecting parameter values for instruction level parallelism.The use of critical quantitative analysis based upon the Simple Scalar simulations is necessary to select optimal parameter values for the processor aimed at specific target environment. This paper aims at finding optimal values for the super scalar processor and determines which processor parameters have the greatest impact on the simulated execution time

A study of tropical tropopause using MST radar

International audienceUsing the MST radar data of vertical wind, the characteristics of the tropical tropopause, following four different definitions, depending on 1) temperature lapse rate, 2) cold point, 3) convective outflow and 4) potential temperature lapse rate minimum, are studied. From the vertical wind data of the radar, the altitude profiles of temperature and horizontal divergence are derived, from which the tropopause levels corresponding to i) the lapse rate ii) cold point iii) convective outflow level and iv) potential temperature lapse rate minimum are determined. The convective outflow level and hence the convective tropopause altitude is determined, for the first time using the MST radar data. The tropopause altitudes and temperatures obtained following the four definitions are compared on a day-to-day basis for the summer and winter seasons. Winter and summer differences in the tropopause altitude and temperature are also studied. Keywords. Meteorology and atmospheric dynamics (convective process; middle atmosphere dynamics; tropical meteorology