Amount Of Thermal Noise Research Articles

The Quantum Analysis of Nonlinear Optical Parametric Processes with Thermal Reservoirs

In this paper, employing the stochastic differential equations associated with the normal ordering, the quantum properties of a nondegenerate three-level cascade laser with a parametric amplifier and coupled to a two-mode thermal reservoir are thoroughly analyzed. Particularly, the enhancement of squeezing and the amplification of photon entanglement of the two-mode cavity light are investigated. It is found that the two cavity modes are strongly entangled and the degree of entanglement is directly related to the two-mode squeezing. Despite the fact that the entanglement and squeezing decrease with the increment of the mean photon number of the thermal reservoir, strong amount of these nonclassical properties can be generated for a considerable amount of thermal noise with the help of the nonlinear crystal introduced into the laser cavity. Moreover, the squeezing and entanglement of the cavity radiation enhance with the rate of atomic injection.

Design and analysis of multibeam communication satellite links operated at Ka Band Frequency in Indonesia

In this paper, we design the link budget of communication satellite. This communication satellite is designed for Ka-Band Frequency for broadband communication in Non-Geostationary Orbit (NGSO) with altitude of 1200 km. The ability of this communication satellite depends on the strength of the signal and the amount of thermal noise. Ka-Band has wider bandwidth and higher data capacity but the drawback of this frequency is it is susceptible to rain attenuation in which Indonesia is an equatorial area that has high rainfall rate, so that the design of communication satellite in Ka-Band needs more consideration to determine satellite system parameter to keep the signal strength great. Indonesia is a wide archipelago country and satellite link design requires beam that can cover all Indonesia with great signal strength and multibeam antenna technology is one of solutions to overcome it. In this research, design and analysis of communication satellite is done using multibeam antenna. The main challenge of the design is to generate the link budget’s result to meet determined parameter. Iterative calculation in design must be used to find an effective link margin and bit rate of this communication satellite. The main result of this research is multi beam satellite provide better performance than single beam satellite in Ka band frequency. The use of BPSK modulation in multi beam satellite shows better performance than other modulation types.

Interaction between noise suppression and inhomogeneity correction in MRI.

While cardiovascular disease is the leading cause of death in most developed countries, SPAMM-MRI can reduce morbidity by facilitating patient diagnosis. An image analysis method with a high degree of automation is essential for clinical adoption of SPAMM-MRI. The degree of this automation is dependent on the amount of thermal noise and surface coil-induced intensity inhomogeneity that can be removed from the images. An ideal noise suppression algorithm removes thermal noise yet retains or enhances the strength of the edges of salient structures. In this paper, we quantitatively compare and rank several noise suppression algorithms in images from both normal and diseased subjects using measures of the residual noise and edge strength and the statistical significance levels and confidence intervals of these measures. We also investigate the interrelationship between inhomogeneity correction and noise suppression algorithms and compare the effect of the ordering of these algorithms. The variance of thermal noise does not tend to change with position; however, inhomogeneity correction increases noise variance in deep thoracic regions. We quantify the degree to which an inhomogeneity estimate can improve noise suppression and whether noise suppression can facilitate the identification of homogeneous tissue regions, and thereby, assist in inhomogeneity correction.

Quantum detection for on-off keyed mixed-state signals with a small amount of thermal noise

The detection strategy proposed previously by the authors for binary pure-state signals, which consists of a unitary transformation and photon counting afterward [Phys. Rev. A 54, 2728 (1996)], can also be applied to the case of on-off keyed signals of coherent states with a small amount of thermal noise. It yields an error level almost the same as the quantum minimum bound in practical parameter region.