نتایج جستجو برای: amplitude shift
تعداد نتایج: 227293 فیلتر نتایج به سال:
It has been previously shown that the amplitude of the ultrasound-stimulated acoustic emission (USAE) signal is sensitive to tissue temperature and, therefore, can help detect it. Its amplitude, however, is sensitive to both acoustical and mechanical parameters, that at most frequencies have opposite effects due to temperature. In this paper, we explore the feasibility of using a frequency shif...
Watermarking is a potential method for copyright protection and authentication of multimedia data in the internet. The watermarking process can be viewed as a communication task, where the watermark acting like information is embedded into a host image acting like noise in a communication channel which is susceptible to all kinds of attacks acting like jamming. In a previous paper, we proposed ...
The reflectance from the iridophores in the skin of the neon tetra Paracheirodon innesi (Myers) and the iridophores in the cornea of the sand goby Pomatoschistus minutus (Pallas) changes in response to light. In both cases the reflectance comes from the constructive interference of alternating plates of material of high and low refractive index. In the neon tetra the high refractive index plate...
In the beginning of 21 st century there has been a dramatic shift in the market dynamics of telecommunication services. The transmission from base station to mobile or downlink transmission using M-ary Quadrature Amplitude modulation (QAM) and Quadrature phase shift keying (QPSK) modulation schemes are considered in Wideband-Code Division Multiple Access (W-CDMA) system. We have done the perfor...
Correlations between 276 orthogonal electrocardiographic measurements and constitutional variables were made in 450 normal women, aged 18 to 90 years. Advancing age led to decreases in amplitudes, left QRS axis shift, rightward and superior displacement of the ST segment, and anterior shift of the T wave. QZ was absent in 1% of normal women over age 40. In the oldest subjects, Ry amplitude was ...
In this letter, we prove that the classical capacity of quantum channel for M symmetric states is achieved by an uniform distribution on a priori probabilities. We also investigate non-symmetric cases such as a ternary amplitude shift keyed signal set and a 16-ary quadrature amplitude modulated signal set in coherent states. PACS numbers: 03.67.-a, 03.67.Hk, 89.70.+c
1. We electrically stimulated the intermediate and deep layers of the superior colliculus (SC) in two rhesus macaques free to move their heads both vertically and horizontally (head unrestrained). Stimulation of the primate SC can elicit high-velocity, combined, eye-head gaze shifts that are similar to visually guided gaze shifts of comparable amplitude and direction. The amplitude of gaze shif...
An eight-phase-shift-keying signal is experimentally de-aggregated onto two four-pulse amplitude modulation signals using nonlinear processes in optical elements. Quadrature-phase-shift-keying signals are similarly de-multiplexed into two binary phase shift keying signals by mapping the data points onto the constellation axes. De-multiplexing performance is evaluated as a function of the optica...
هدف: این مطالعه به منظور بررسی یافته های تست پتانسیل برانگیخته از بینایی در افراد کاندید عمل lasik در پلی کلینیک قدس در سالهای 88 و 89 انجام شده است. روش مطالعه: این مطالعه به صورت یک بررسی توصیفی - تحلیلی مقطعی انجام شده است. حجم نمونه مورد بررسی در این مطالعه شامل 25 نفر بود که تحت درمان به شیوه lasik قرار گرفته بودند. نحوه انتخاب افراد نیز به صورت تصادفی ساده بود. یافته ها: میانگین میزان l...
ارائه راهکارهایی مناسب جهت تشخیص دقیق تر و بهتر گلوکوم مادرزادی و جلوگیری از پیشرفت آن. روش مطالعه: 50 کودک مبتلا به گلوکوم مادرزادی (گروه case) و 50کودک سالم (گروه control) در این مطالعه مورد بررسی قرار گرفتند. هر دو گروه مورد معاینه قرار گرفتند وتست پتانسیل برانگیخته از بینایی((vep روی آنها انجام شد. متغیرهای اندازه گیری شده شامل تاخیر فاز(latency) ودامنه(amplitude) بودند.نتایج ثبت و فراوا...
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